The Aldol Reaction of Allenolates with Aldehydes in the Presence of Magnesium Diiodide (MgI2) as Catalyst

✍ Scribed by Guang-Hui Deng; Hui Hu; Han-Xun Wei; Paul W. Paré

• Book ID: 102256192
• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: German
• Weight: 82 KB
• Volume: 86
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200390294

✦ Synopsis

Abstract

Stereoselective synthesis of (Z)‐α‐(hydroxyalkyl)‐β‐iodoacrylates (=(2__Z__)‐2‐(hydroxyalkyl)‐3‐iodoprop‐2‐enoates) was achieved in a one‐pot coupling reaction from methyl prop‐2‐ynoate, Me~3~SiI, and an alkanal under mild conditions with MgI~2~ as catalyst (→ 1–9; see Table and Scheme 1). Baylis‐Hillman β‐iodo adducts were generated in excellent yields with high (Z)‐selectivity. The conversion of methyl prop‐2‐ynoate to an active methyl 3‐iodo‐1‐[(trimethylsilyl)oxy]allenolate intermediate in situ followed by carbonyl addition is proposed as the reaction sequence (Schemes 1 and 2).