Asymmetric synthesis of corsifuran A by an enantioselective oxazaborolidine reduction.

Corsifuran A has been prepared in an enantiomerically pure form for the first time by an asymmetric reduction procedure, allowing confirmation of the absolute stereochemistry of the natural product as (R).

Synthetic applicability and in situ recycling of a B-methoxy oxazaborolidine catalyst derived from cis-1-amino-indan-2-ol.

A procedure is described that greatly simplifies the use of an oxazaborolidine catalyst derived from (1R,2S) cis-1-amino-indan-2-ol. This B-OMe catalyst has been employed in the asymmetric reduction of a number of structurally diverse prochiral ketones, in particular the reduction of alpha-amino acetophenone and its derivatives. A method for reducing the effective catalyst loading by "in situ recycling" is also presented.