Affordable Access

Publisher Website

Enantio- and Diastereoselective Additions to Aldehydes Using the Bifunctional Reagent 2-(Chloromethyl)-3-(tributylstannyl)propene: Application to a Synthesis of the C16–C27 Segment of Bryostatin 1

Authors
Journal
The Journal of Organic Chemistry
0022-3263
Publisher
American Chemical Society
Publication Date
Volume
70
Issue
7
Identifiers
DOI: 10.1021/jo048308m
Keywords
  • Article

Abstract

Reactions of the bifunctional allylstannane 2-(chloromethyl)-3-(tributylstannyl)propene with aldehydes have been examined. These generally occur in high yields using Lewis acid promoters and the products can be isolated and purified without incident. Good yields and high enantioselectivities are also realized in catalytic asymmetric allylations (CAA reactions) using the previously described BITIP catalyst system. Protection of the free hydroxyl can be accomplished without cyclization to the derived tetrahydrofuran, although this transformation is also facile. The utility of the incorporated allyl chloride functionality allows for the obvious use of such products in reactions with nucleophiles. Use of these products in a less obvious connective strategy is demonstrated in the synthesis of the C12–C27 segment of bryostatin 1 where a connective, or “lynchpin”, double-allylation process was employed. The β-hydroxy allyl chloride obtained from an initial chelation-controlled allylation of aldehyde 16 was converted to allylstannane 19 and applied in a second allylation reaction, thus allowing for a highly convergent synthesis of the bryostatin C ring backbone in a stereoselective fashion.

There are no comments yet on this publication. Be the first to share your thoughts.