Stereoselective <i>trans-</i> and <i>cis-</i>Dihydroxylations of 2<i>H</i>-Pyranyl and Dihydropyridinyl Heterocycles Synthesized from Formal [3 + 3]-Cycloaddition Reactions of α,β-Unsaturated Iminium Ions with 1,3-Dicarbonyl Equivalents<sup>†</sup>
作者:Luke R. Zehnder、Lin-Li Wei、Richard P. Hsung、Kevin P. Cole、Michael J. McLaughlin、Hong C. Shen、Heather M. Sklenicka、Jiashi Wang、Craig A. Zificsak
DOI:10.1021/ol010034r
日期:2001.7.1
[GRAPHICS]We describe here an inherent problem in direct epoxidation of the endocyclic olefin in 2H-pyrans fused to 2-pyrones, Such difficulties led to the development of highly stereoselective trans- and cis-dihydroxylations of these olefinic systems in both 2H-pyrans and dihydropyridines fused to a 2-pyrones or a 2-cyclohexenone. Protocols for the removal of the activated allylic hydroxyl group are also reported.