Preparation of 2,4-Disubstituted Cyclopentenones by Enantioselective Iridium-Catalyzed Allylic Alkylation: Synthesis of 2′-Methylcarbovir and TEI-9826

✍ Scribed by Pierre Dübon; Mathias Schelwies; Günter Helmchen

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 432 KB
• Volume: 14
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200800495

✦ Synopsis

Abstract

A broadly applicable synthesis of chiral 2‐ or 2,4‐substituted cyclopent‐2‐enones has been developed by combining asymmetric iridium‐catalyzed allylic alkylation reactions and ruthenium‐catalyzed ring‐closing metathesis. Enantiomeric excesses (ee values) in the range of 95–99 % ee have been achieved. This method offers a straightforward access to biologically active prostaglandins of the PGA type. As an example, an enantioselective synthesis of the prostaglandin‐analogue 13,14‐dihydro‐15‐deoxy‐Δ^7^‐prostaglandin‐A1‐methyl ester (TEI‐9826) has been carried out. Furthermore, the carbonucleoside 2′‐methylcarbovir has been prepared from O‐protected 4‐hydroxymethyl‐2‐methyl‐cyclopent‐2‐enone by Pd‐catalyzed allylic amination.