ChemInform Abstract: Enantioselective Cyclopropanation of Allylic Alcohols with Dioxaborolane Ligands: Scope and Synthetic Applications.

✍ Scribed by Andre B. Charette; Helene Juteau; Helene Lebel; Carmela Molinaro

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 37 KB
• Volume: 30
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199915099

✦ Synopsis

Enantioselective Cyclopropanation of Allylic Alcohols with Dioxaborolane Ligands: Scope and Synthetic Applications.

-Chiral dicarboxamidodioxaborolane is found to be a very efficient chiral controller for the conversion of allylic alcohols (I) to enantiomeric cyclopropylmethanols (III) using bis(iodomethyl)zinc. The reaction can be successfully applied to the stereoselective monocyclopropanation of the allylic double bond in polyenols like geraniol (Ih) or 2,4-dienols (IV) and (VI) (mono-: dicyclopropane derivatives ≥ 8 : 1). Homoallylic alcohols (VIII) are also smoothly converted to chiral cyclopropylethanols (IX). Cyclopropanation of allylic carbamate (X) proceeds only with low yield and moderate stereoselectivity, however, cyclopropylmethylcarbamate (XII) is readily available by Mitsunobu reaction of cyclopropylmethanol (IIIa).

-(CHARETTE,