Pestalotiopsin A. Enantioselective Construction of Potential Building Blocks Derived from Antipodal Cyclobutanol Intermediates
作者:Leo A. Paquette、Gregory D. Parker、Takahiro Tei、Shuzhi Dong
DOI:10.1021/jo070861r
日期:2007.9.1
[GRAPHICS]D-Glyceraldehyde acetonide has been used as the starting point for accessing the enantiomeric cyclobutanols 11 in optically pure condition. The dextrorotatory enantiomer has been transformed in five steps into the [3.2.0] bicyclic lactone 22. While the deoxygenation of 22 proved to be problematical, the uncyclized variant 25 underwent the Barton process smoothly. These findings guided the related conversion of (-)-11 into 34. Use was also made of ring-closing metathesis to bring about the conversion of (+)-11 into [4.2.0] bicyclic lactone building blocks. In general, all three pathways are efficient and offer the prospect of practical side-chain appendage for the purpose of installing the nine-membered ring of pestalotiopsin A (1).