Patent ID: 8283502
Filing Date: 2012-10-09
Classification: C07B,C07C

Abstract:
1. A process for the preparation of a compound of formula or mirror image wherein R R A is selected from the group consisting of C wherein A and R said process comprising the steps of (i) preparing a mixture of a zinc(II) catalyst, an initial amount of the compound of formula I in a molar ratio to the zinc(II) catalyst from 0.1:1 to 2:1, and optionally a further chiral auxiliary in a molar ratio to the zinc(II) catalyst of 0.1:1 to 3:1, and (ii) adding to said mixture at a temperature from −78 to 30° C., and (iii) heating the mixture obtained in step (ii) to 10 to 50° C. until completion of the reaction, to obtain the compound of formula I.