Since the discovery of the titanium-catalyzed asymmetric epoxidation of allylic alcohols in 1980,1 ongoing efforts in these laboratories have been directed toward expanding the scope and synthetic utility of the reaction. A serious limitation of the original procedure has been its failure when applied to substrates with a strong propensity for undergoing ring-opening reactions. Of the many reaction modifications which have been explored, the recent development of an effective catalytic procedure2 has offered the most general solution to this important problem and has allowed even allyl alcohol to be included for the first time on the roster of successful substrates. Although a full description of this new development will be reported shortly, the practical importance of homochiral glycidol in the synthesis of β-adrenergic blocking agents (β-blockers) prompts us to disclose here two very efficient routes to (2S)-propranolol, each utilizing the asymmetric epoxidation of allyl alcohol.
|Number of pages||3|
|Journal||Journal of Organic Chemistry|
|State||Published - 1986|