An alternative stereoselective synthesis of the macrocylic fragrances (R)-12-methyltridecanolide and (S)-muscolide by means of an asymmetric catalytic conjugate addition/Baeyer-Villiger oxidation

We show herein an alternative catalytic, highly enantioselective approach to (R)-12-methyltridecanolide and (S)-muscolide, that is, chiral macrocyclic lactones which are good musk odorants. In fact, they can be efficiently prepared by a sequence of reactions consisting of a catalytic asymmetric conjugated addition of dimethylzinc to suitable α,β-unsaturated enones followed by a Baeyer-Villiger oxidation. Interestingly, high enantiomeric excesses (up to 92%) are obtained in the asymmetric conjugate addition by means of the 'tropos' phosphoramidite L1. © 2006 Elsevier Ltd. All rights reserved.