Enantioselective Deprotonation of meso-Cycloheptanone Derivative:  Application to the Synthesis of a Potential Intermediate for Pseudomonic Acid B

Abstract

[reaction: see text] A novel synthetic path to a potential intermediate for the synthesis of pseudomonic acid B was established by employing enantioselective deprotonation of a meso-cycloheptanone derivative bearing hydroxy groups at the 3,4,5,6-positions with lithium (S,S')-alpha,alpha'-dimethyldibenzylamide as a key step.

Stereoselective Functionalization of Dihydropyran‐3‐ols: Application to the Synthesis of Enantiopure Ethyl Deoxymonate B

“…Because the dihydroxylation of readily available cis 3,6‐disubstituted dihydropyranyl‐3‐ols is highly stereoselective (see before), we considered an approach to pseudomonic acid B, with an additional hydroxy group at C‐8, from a sulfinyldihydropyran intermediate with the appropriate functionalization at C‐2. Note that the preparation of pseudomonic acid B and related compounds with a hydroxy group at C‐8 is comparatively less studied 21g,22. Scheme shows our retrosynthetic analysis for methyl and ethyl deoxymonates B ( 29 and 30 ), which should be available by homologation of the side‐chain at C‐8 of intermediate C by a cross‐metathesis reaction in the presence of a free hydroxy group at C‐8, inspired by the work of Markó and co‐workers,21h followed by olefination to build the C‐5 side‐chain.…”