Intramolecular prins reaction and catalysts suitable therefor (citronellal to isopulegol)

Abstract

Processes for the preparation of a compound of the formula (B) having the following steps: provision of a compound of the formula (A), intramolecular reaction of the compound of the formula (A) in the presence of an aluminium siloxide of the formula (I) wherein in formula (I) the radicals R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″ independently of one another denote hydrogen or an organic radical, are described.

1 - 17 . (canceled) 
   
   
       18 . A process for the preparation of a compound of the formula B 
     
       
         
         
             
             
         
       
       comprising:
 providing a compound of the formula A 
 
     
     
       
         
         
             
             
         
       
       
         reacting the compound of the formula A in an intramolecular reaction in the presence of an aluminium siloxide of the formula (I) 
       
     
     
       
         
         
             
             
         
       
       wherein R 1 , R 2 , R 3  in each case independently of one another are hydrogen or methyl, R 4  is hydrogen or an alkyl radical having 1 to 6 C atoms, and n is 0, 1 or 2 
       and wherein R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are hydrogen or an organic radical, with the proviso that at least one of the radicals R a′ , R a″ , R a″  and one of the radicals R b′ , R b″ , R b′″  and one of the radicals R c′ , R c″ , R c′″  is not hydrogen; and 
       independently of one another also two or three of the radicals R a′ , R a″ , R a′″ , two or three of the radicals R b′ , R b″ , R b′″  and two or three of the radicals R c′ , R c″ , R c′″  can be covalently bonded to one another. 
     
   
   
       19 . The process of  claim 18 , wherein:
 R 1  and R 2  in each case independently of one another are hydrogen or methyl,   R 3  is hydrogen,   R 4  is methyl, and   n is 0 or 1.   
   
   
       20 . The process of  claim 18 , wherein the compound of the formula A is chosen from the group consisting of 2,6-dimethyl-5-heptenal and citronellal (3,7-dimethyl-6-octenal). 
   
   
       21 . The process of  claim 18 , wherein the aluminium siloxide of the formula (I) is prepared in situ and/or is freshly prepared. 
   
   
       22 . The process of  claim 18 , wherein the intramolecular reaction of the compound of the formula A is carried out in a diluent, the boiling point of which is higher than that of the compounds of the formulae A and B; or
 after the intramolecular reaction of the compound of the formula A has taken place, a diluent, the boiling point of which is higher than that of the compounds of the formulae A and B, is added,   said process further comprising:   separating off, by distillation, the compound of the formula B from the diluent and the aluminium siloxide of the formula (I).   
   
   
       23 . The process of  claim 18 , further comprising
 recycling the aluminium siloxide of the formula (I) in the intramolecular reaction of the compound of the formula A.   
   
   
       24 . A process for the preparation of a compound of the formula B 
     
       
         
         
             
             
         
       
       comprising:
 providing a compound of the formula A 
 
     
     
       
         
         
             
             
         
       
       
         mixing and/or reacting 
       
       either an aluminium compound of the formula (III)
   H p Al(R 5 ) 3-p   (III) 
 
       wherein R 5  is an alkyl radical having 1 to 4 C atoms or an aryl radical and 
       p is 0, 1 or 2; 
       or an aluminium compound of the formula (IV)
   MAlH 4   (IV) 
 
       wherein M is lithium, sodium or potassium; 
       with silanols of the formulae (IIa), (IIb) and (IIc), 
     
     
       
         
         
             
             
         
       
       which can be identical or different, 
       wherein R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″ , independently of one another are hydrogen or an organic radical, with the proviso that at least one of the radicals R a′ , R a″ , R a′″  and one of the radicals R b′ , R b″ , R b′″  and one of the radicals R c′ , R c″ , R c′″ , is not hydrogen, 
       wherein independently of one another also two or three of the radicals R a′ , R a″ , R a′″ , two or three of the radicals R b′ , R b″ , R b  and two or three of the radicals R a′ , R a″ , R a′″ , can be covalently bonded to one another; and
 reacting the compound of the formula A in an intramolecular reaction in the presence of the mixture and/or the reaction product of the reaction of the aluminium compound (III) or (IV) with the silanols (IIa), (IIb) and (IIc). 
 
     
   
   
       25 . The process of  claim 24 , wherein the reaction production of the reaction of the aluminium compound (III) or (IV) with the silanols (IIa), (IIb) and (IIc) is prepared in situ and/or is freshly prepared. 
   
   
       26 . The process of  claim 24 , wherein the intramolecular reaction of the compound of the formula A is carried out in a diluent, the boiling point of which is higher than that of the compounds of the formulae A and B; or
 after the intramolecular reaction of the compound of the formula A has taken place, a diluent, the boiling point of which is higher than that of the compounds of the formulae A and B, is added,   said process further comprising:   separating off, by distillation, the compound of the formula B from the diluent and the reaction product of the reaction of the aluminium compound (III) or (IV) with the silanols (IIa), (IIb) and (IIc).   
   
   
       27 . A process comprising undergoing a chemical reaction in the presence of a catalyst selected from the group consisting of
 an aluminium siloxide of the formula (I)   
     
       
         
         
             
             
         
       
       and
 a mixture and/or a reaction product of a reaction either of an aluminium compound of the formula (III)
   H p Al(R 5 ) 3-p   (III) 
 
 
       wherein 
       R 5  is an alkyl radical having 1 to 4 C atoms or an aryl radical and 
       p is 0, 1 or 2, 
       or of an aluminium compound of the formula (IV)
   MAlH 4   (IV) 
 
       wherein M is chosen from lithium, sodium or potassium; 
       with silanols of the formulae (IIa), (IIb) and (IIc), 
     
     
       
         
         
             
             
         
       
       which can be identical or different, 
       wherein R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are hydrogen or an organic radical, with the proviso that at least one of the radicals R a′ , R a″ , R a′″  and one of the radicals R b′ , R b″ , R b′″  and one of the radicals R c′ , R c″ , R c′″  is not hydrogen, and 
       wherein independently of one another also two or three of the radicals R a′ , R a″ , R a′″ , two or three of the radicals R b′ , R b″ , R b′″  and two or three of the radicals R c′ ; R c″ , R c″  can be covalently bonded to one another. 
     
   
   
       28 . The process of  claim 27 , wherein the reaction is an intramolecular Prins reaction. 
   
   
       29 . The process of  claim 27 , wherein the chemical reaction produces a compound of the formula B 
     
       
         
         
             
             
         
       
       from a compound of the formula A 
     
     
       
         
         
             
             
         
       
       wherein in the formulae A and B, R 1 , R 2 , R 3  and n in each case have the same meaning and 
       R 1 , R 2 , R 3  in each case independently of one another are hydrogen or methyl, R 4  is hydrogen or an alkyl radical having 1 to 6 C atoms, and n is 0, 1 or 2. 
     
   
   
       30 . The process of  claim 18 , wherein
 R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are an optionally substituted radical chosen from the group consisting of C 1 -C 20 -alkyl, C 1 -C 20 -heteroalkyl, C 3 -C 20 -cycloalkyl, C 4 -C 20 -cycloalkylalkyl, C 2 -C 20 -alkenyl, C 3 -C 20 -cycloalkenyl, C 4 -C 20 -cycloalkenylalkyl, C 2 -C 20 -alkynyl, C 5 -C 20 -cycloalkylalkynyl, C 1 -C 20 -alkoxy, C 3 -C 20 -cycloalkoxy, C 1 -C 20 -cycloalkylalkoxy, C 3 -C 25 -aryl, C 2 -C 25 -heteroaryl, C 4 -C 2 -arylalkyl, C 8 -C 25 -cycloalkylaryl, C 9 -C 25 -cycloalkenylaryl, C 5 -C 25 -cycloalkylheteroaryl, C 8 -C 25 -heterocycloalkylaryl, C 8 -C 25 -heterocycloalkenylaryl, C 8 -C 25 -heterocycloalkenylheteroaryl and C 3 -C 25 -heteroarylalkyl; and wherein independently of one another also two or three of the radicals R a′ , R a″ , R a′″ , two or three of the radicals R b′ , R b″ , R b′″  and two or three of the radicals R c′ , R c″ , R c′″  may be covalently bonded to one another.   
   
   
       31 . An aluminium siloxide of the formula (I) 
     
       
         
         
             
             
         
       
       wherein: 
       R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are an optionally substituted radical chosen from the group consisting of C 3 -C 25 -aryl, C 2 -C 25 -heteroaryl, C 4 -C 25 -arylalkyl, C 8 -C 25 -cycloalkylaryl, C 8 -C 25 -cycloalkenylaryl, C 5 -C 25 -cycloalkylheteroaryl, C 9 -C 25 -heterocycloalkylaryl, C 8 -C 25 -heterocycloalkenylaryl, C 8 -C 25 -heterocycloalkenylheteroaryl and C 3 -C 25 -heteroarylalkyl, 
       excluding the compound Al(OSiPh 3 ) 3 . 
     
   
   
       32 . A mixture
 either of an aluminium compound of the formula (III)
   H p Al(R 5 ) 3-p   (III) 
   wherein R 5  is an alkyl radical having 1 to 4 C atoms or an aryl radical and   p is 0, 1 or 2;   or of an aluminium compound of the formula (IV)
   MAlH 4   (IV) 
   wherein M is chosen from lithium, sodium or potassium,   with silanols of the formulae (IIa), (IIb) and (IIc),   
     
       
         
         
             
             
         
       
       which can be identical or different, 
       wherein in the formulae (IIa), (IIb) and (IIc): 
       R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are an optionally substituted radical chosen from the groups consisting of C 3 -C 25 -aryl, C 2 -C 25 -heteroaryl, C 4 -C 25 -arylalkyl, C 8 -C 25 -cycloalkylaryl, C 8 -C 25 -cycloalkenylaryl, C 5 -C 25 -cycloalkylheteroaryl, C 8 -C 25 -heterocycloalkylaryl, C 8 -C 25 -heterocycloalkenylaryl, C 8 -C 25 -heterocycloalkenylheteroaryl and C 3 -C 25 -heteroarylalkyl, 
       wherein the compound comprises no AlMe 3  and/or HOSiPh 3 . 
     
   
   
       33 . A reaction product of a reaction
 either of an aluminium compound of the formula (III)
   H p Al(R 5 ) 3-p   (III) 
   wherein R 5  is an alkyl radical having 1 to 4 C atoms or an aryl radical and   p is 0, 1 or 2;   or of an aluminium compound of the formula (IV)
   MAlH 4   (IV) 
   wherein M is chosen from lithium, sodium or potassium,   with silanols of the formulae (IIa), (IIb) and (IIc),   
     
       
         
         
             
             
         
       
       which can be identical or different, 
       wherein in the formulae (IIa), (IIb) and (IIc): 
       R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are an optionally substituted radical chosen from the group consisting of C 3 -C 25 -aryl, C 2 -C 25 -heteroaryl, C 4 -C 25 -arylalkyl, C 8 -C 25 -cycloalkylaryl, C 8 -C 25 -cycloalkenylaryl, C 5 -C 25 -cycloalkylheteroaryl, C 8 -C 25 -heterocycloalkylaryl, C 8 -C 25 -heterocycloalkenylaryl, C 8 -C 25 -heterocycloalkenylheteroaryl and C 3 -C 25 -heteroarylalkyl, 
       excluding the compound Al(OSiPh 3 ) 3 . 
     
   
   
       34 . The aluminium siloxide of  claim 31 , wherein:
 R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are an optionally substituted radical chosen from the group consisting of C 6 -C 20 -aryl, C 3 -C 20 -heteroaryl, C 7 -C 20 -arylalkyl, C 8 -C 20 -cycloalkylaryl, C 9 -C 20 -cycloalkenylaryl, C 6 -C 20 -cycloalkylheteroaryl, C 9 -C 20 -heterocycloalkylaryl, C 9 -C 20 -heterocycloalkenylaryl, C 8 -C 20 -heterocycloalkenylheteroaryl and C 4 -C 20 -heteroarylalkyl.   
   
   
       35 . The aluminium siloxide of  claim 31 , wherein:
 R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are an optionally substituted radical chosen from the group consisting of C 6 -C 20 -aryl, C 3 -C 20 -heteroaryl, C 8 -C 20 -cycloalkylaryl, C 9 -C 20 -cycloalkenylaryl, C 7 -C 20 -cycloalkylheteroaryl, C 8 -C 20 -heterocycloalkylaryl, C 8 -C 20 -heterocycloalkenylaryl and C 8 -C 20 -heterocycloalkenylheteroaryl.   
   
   
       36 . The process of  claim 18 , wherein, for the aluminium siloxide of the formula (I) and the silanols of the formulae (IIa), (IIb) and (IIc):
 the radicals R a′ , R a″ , R a′″  are identical, the radicals R b′ , R b″ , R b′″  are identical and the radicals R c′ , R c″ , R c′″  are identical.   
   
   
       37 . The process of  claim 24 , wherein
 R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are an optionally substituted radical chosen from the group consisting of C 1 -C 20 -alkyl, C 1 -C 20 -heteroalkyl, C 3 -C 20 -cycloalkyl, C 4 -C 20 -cycloalkylalkyl, C 2 -C 20 -alkenyl, C 3 -C 20 -cycloalkenyl, C 4 -C 20 -cycloalkenylalkyl, C 2 -C 20 -alkynyl, C 5 -C 20 -cycloalkylalkynyl, C 1 -C 20 -alkoxy, C 3 -C 20 -cycloalkoxy, C 5 -C 20 -cycloalkylalkoxy, C 3 -C 25 -aryl, C 2 -C 25 -heteroaryl, C 4 -C 25 -arylalkyl, C 8 -C 25 -cycloalkylaryl, C 9 -C 25 -cycloalkenylaryl, C 5 -C 25 -cycloalkylheteroaryl, C 8 -C 25 -heterocycloalkylaryl, C 8 -C 25 -heterocycloalkenylaryl, C 8 -C 25 -heterocycloalkenylheteroaryl and C 3 -C 25 -heteroarylalkyl; and wherein independently of one another also two or three of the radicals R a′ , R a″ , R a′″ , two or three of the radicals R b′ , R b″ , R b″  and two or three of the radicals R c′ , R c″ , R c′″  may be covalently bonded to one another.   
   
   
       38 . The process of  claim 18 , wherein in formula (I)
 R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independently of one another are hydrogen or an optionally substituted radical chosen from the group consisting of alkyl, heteroalkyl, cycloalkyl, cycloalkylalkyl, alkenyl, cycloalkenyl, cycloalkenylalkyl, alkynyl, cycloalkylalkynyl, alkoxy, cycloalkoxy, cycloalkylalkoxy, aryl, heteroaryl, arylalkyl, cycloalkylaryl, cycloalkenylaryl, cycloalkylheteroaryl, heterocycloalkylaryl, heterocycloalkenylaryl, heterocycloalkenylheteroaryl and heteroarylalkyl, with the proviso that at least one of the radicals R a′ , R a″ , R a′″  and one of the radicals R b′ , R b″ , R b′″  and one of the radicals R c′ , R c″ , R c′″  is not hydrogen;   wherein independently of one another also two or three of the radicals R a′ , R a″ , R a′″ , two or three of the radicals R b′ , R b″ , R b′″  and two or three of the radicals R c′ , R c″ , R c′″  can be covalently bonded to one another.   
   
   
       39 . The process of  claim 24 , wherein R a′ , R a″ , R a′″ , R b′ , R b″ , R b′″ , R c′ , R c″ , R c′″  independent of one another are hydrogen or an optionally substituted radical chosen from the group consisting of alkyl, heteroalkyl, cycloalkyl, cycloalkylalkyl, alkenyl, cycloalkenyl, cycloalkenylalkyl, alkynyl, cycloalkylalkynyl, alkoxy, cycloalkoxy, cycloalkylalkoxy, aryl, heteroaryl, arylalkyl, cycloalkylaryl, cycloalkenylaryl, cycloalkylheteroaryl, heterocycloalkylaryl, heterocycloalkenylaryl, heterocycloalkenylheteroaryl and heteroarylalkyl, with the proviso that at least one of the radicals R a′ , R a″ , R a′″  and one of the radicals R b′ , R b″ , R b′″  and one of the radicals R c′ , R c″ , R c′″  is not hydrogen,
 wherein independently of one another also two or three of the radicals R a′ , R a″ , R a′″ , two or three of the radicals R b′ , R b″ , R b′″  and two or three of the radicals R c′ , R c″ , R c′″  can be covalently bonded to one another.   
   
   
       40 . The process of  claim 24 , wherein
 R 1  and R 2  in each case independently of one another are hydrogen or methyl,   R 3  is hydrogen,   R 4  is methyl, and   n is 0 or 1.