Enantioselective Total Synthesis and Absolute Configuration of the Natural Norsesquiterpene 7-Demethyl-2-methoxycalamenene by a Silane-Terminated Intramolecular Heck Reaction

✍ Scribed by Tietze, Lutz F. ;Raschke, Thomas

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 774 KB
• Volume: 1996
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199619961207

✦ Synopsis

Abstract

The total synthesis of the norsesquiterpene 7‐demethyl‐2‐methoxycalamenene (1) by a newly developed enantioselective silane‐terminated Heck reaction is described. The Pd^0^‐catalyzed transformation of the allylsilane 7, obtained from 3‐(3‐methoxyphenyl)propanol (2) in 7 steps, provides the tetralin 8 in 91% yield and with 92% ee in the presence of (R)‐BINAP. Transformation of 8 via 14 and 15 gives 1. The absolute configuration of 1 which has previously not been known was deduced from a single‐crystal X‐ray analysis of 10, obtained from the cyclization product 8 by hydroboration and acylation with camphanic acid chloride.