Chromium(II) mediated threo selective synthesis of homoallyl alcohols

✍ Scribed by Tamejiro Hiyama; Keizo Kimura; Hitosi Nozaki

• Book ID: 104235189
• Publisher: Elsevier Science
• Year: 1981
• Tongue: French
• Weight: 261 KB
• Volume: 22
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)82859-8

✦ Synopsis

Remarkable threo selectivity is observed in the reaction of aldehydes with tm-and c&s-1-bromo-2-butene with the aid of chromium(H) salts. Solvent effect as well as the synthetic application is discussed.

How to attain acyclic stereoselection is of great importance in modern synthetic methodologies.

A solution to this end may be presented by use of a variety of metals as the gegen ion of carbanion species. 1

In this sense chromium(I1) mediated Barbier-Grignard reaction of ally1 halides with aldehydes or ketones .-.

exhibits remarkable feature:' 1-bromo-2-butene and benzaldehyde give only one diastereomer of a-methyl-1-phenyl-3-buten-l-01 whose stereochemistry has been determined to be threo by Heathcock and his coworker.

3 We wish to report the threo selectivity is valid for various aldehydes, 4 and is characteristic of chromium in contrast to main group metals.