From 2-Aminomethyl-1,4-benzodioxane Enantiomers to Unichiral 2-Cyano- and 2-Carbonyl-Substituted Benzodioxanes via Dichloroamine

摘要

2-Substituted 1,4-benzodioxanes, such as 2-cyano-, 2-methoxycarbonyl-, 2-aminocarbonyl-, and 2-formyl-1,4-benzodioxane, are key synthons that for the most part are never described as enantiomers or are inadequately characterized for enantiomeric purity. They were prepared by quantitative N,Ndichlorination of (R)- and (S)-2-aminomethyl-1,4-benzodioxane and successive functional group conversions in high yields without any racemization of the stereogenic benzodioxane C(2).