A Novel NaI-Promoted Ring Expansion of Cyclopropylidene Alcohols to Dihydropyrans
作者:Xian Huang、Weijun Fu、Ying Lin
DOI:10.1055/s-2007-968016
日期:2007.2
A novel and efficient approach to prepare dihydropyrans via the ringexpansion of cyclopropylidene alcohols in the presence of NaI in AcOH-MeCN was reported. The key feature in the transformation is the effect of the iodide anion.
报道了一种在 AcOH-MeCN 中在 NaI 存在下通过环丙叉醇的扩环来制备二氢吡喃的新型有效方法。转化的关键特征是碘阴离子的作用。
A concise and enantioselective approach to cyclobutanones by tandem asymmetric epoxidation and enantiospecific ring expansion of cyclopropylidene alcohols. An enantiocontrolled synthesis of (+)- and (-)-.alpha.-cuparenones
A tandem Katsuki-Sharpless asymmetric epoxidation and enantiospecific ring expansion of 2-alkyl(or 2-aryl)-2-cyclopropylideneethanols (1a-i) afforded chiral 1-alkyl(or 1-aryl)-1-(hydroxymethyl)cyclobutanones (3a-i) in high yields and high enantiomeric excess. These compounds are potentially valuable synthons for the enantioselective creation of the quaternary carbons. Hence, this enabled us to accomplish a concise and enantioselective total synthesis of both (+)- and (-)-alpha-cuparenones (11).