Enantioselective Total Synthesis of Spirofungins A and B
作者:Michael T. Crimmins、Elizabeth A. O’Bryan
DOI:10.1021/ol101961c
日期:2010.10.1
The enantioselective total synthesis of spirofungins A (1) and B (2) is reported in 14 steps over the longest linear sequence. Key steps include the use of thiazolidinethione-mediated aldol reactions to assemble the major fragments and installation of the C1-C6 side chain using a cross metathesis reaction.
Dramatic Solvent Effect on the Diastereoselectivity of Michael Addition: Study toward the Synthesis of the ABC Ring System of Hexacyclinic Acid
作者:Julie Toueg、Joëlle Prunet
DOI:10.1021/ol702566c
日期:2008.1.1
During our studies toward the synthesis of the ABC ring system of hexacyclinic acid, we have observed a dramatic influence of the solvent on both our key steps. The diastereoselectivity of the intermolecular Michael addition could be totally reversed by changing the polarity of the solvent, and trifluoroethanol was found to be the optimal solvent for the following Mn(III)-promoted radical cyclization.