Stereoselective Synthesis of Alcohols, L. Stereoselective Synthesis of a C-15/C-27 Segment of the Venturicidines

✍ Scribed by Hoffmann, Reinhard W. ;Rolle, Ulrike ;Göttlich, Richard

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 946 KB
• Volume: 1996
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199619961104

✦ Synopsis

Abstract

Chain extension of an aldehyde by two “propionate” units has been attained by stereoselective allylboration with the chiral 1‐methylbutenyl boronate 3 to give, e.g., the homoallylic alcohol 6, followed by a regioselective hydroboration/carbonylation procedure to give, e.g., the epimeric aldehydes 8. The latter were converted into the lactols 10, which equilibrated to the desired epimer. The lactols could again be subjected to an allylboration reaction, initiating a second round of the chain extension protocol. This technique has been used to synthesize in 15 steps the venturicidene C‐15/C‐27 segment 23, containing 8 stereogenic centers with the proper absolute configuration.