A Highly Stereoselective Approach to the Synthesis of Functionalized Pyran Derivatives by Lewis Acid Assisted Ketal Reduction and Allylation
作者:Suzanne Bogaczyk、Marc-Raleigh Brescia、Yvonne C. Shimshock、Philip DeShong
DOI:10.1021/jo010252y
日期:2001.6.1
of bicyclic ketal 1 gave functionalized pyran derivatives 7a or 7b in a highly stereoselective manner, depending upon the reduction conditions utilized. For example, treatment of ketal 1 with TiCl4/Et3SiH produced exclusively diol 7b with the 2,5-syn relationship in good yield. Alternatively, reduction of ketal 1 by DIBALH gave 2,5-anti-diol 7a stereoselectively. Alane reductions of ketal 1 were highly