Asymmetric synthesis catalyzed by (S)‐alanine‐N‐propylamide as a terminal model of poly[(S)‐alanine]

The asymmetric addition of 1‐dodecanethiol (1) to isopropenyl methyl ketone (2) catalyzed by (S)‐alanine‐N‐propylamide (5) as a terminal model of poly[(S)‐alanine] (3c) was studied. When the asymmetric addition reaction was carried out in chloroform, it was accompanied with a slow competitive racemization of the product by the catalyst. On the other hand, when ethanol was added to the reaction system, the racemization was much depressed.