ChemInform Abstract: Directing Effect of a Neighboring Aromatic Group in the Cyclopropanation of Allylic Alcohols.

✍ Scribed by J. COSSY; N. BLANCHARD; C. MEYER

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 33 KB
• Volume: 30
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199903073

✦ Synopsis

Directing Effect of a Neighboring Aromatic Group in the Cyclopropanation of Allylic Alcohols.

-Various racemic allylic alcohols are stereoselectively transformed to cyclopropanes with I-CH 2 -Cl in the presence of either zinc or samarium reagent. Alcohols bearing an aryl group at the stereocenter at the remote allylic position show a reversal of stereoselectivity by changing from zinc to samarium promotion. Additionally, the Zn-promoted cyclopropanation of the (E)-isomer (V) exhibits a diastereoisomeric ratio of products comparable to the one for the (Z)-isomer (I). -(COSSY, J.;