High stereo selection of three carbon centers containing a methyl substituent has been realized. The conjugate addition of dimethylcuprate to 5-methyl-2-cyclohexenone I followes by acetal formation with crotyl alcohol and then subsequent Claisen rearr...
High stereo selection of three carbon centers containing a methyl substituent has been realized. The conjugate addition of dimethylcuprate to 5-methyl-2-cyclohexenone I followes by acetal formation with crotyl alcohol and then subsequent Claisen rearrangement produces three-methyl substituted cyclohexanone 3. When the same sequence of reactions was applied to 3,5-dimethyl-2-cyclohexenone 2, where copper-hydride was used instead of dimethylcuprate, 4 was obtaines in a highly stereo selective manner. These two cyclohexenones 3 and 4 can be cleaved to produce tri-propionate chains 5 and 6, respectively.