Asymmetric Total Synthesis of Neoxaline

Abstract

A first asymmetric total synthesis and determination of the absolute configuration of neoxaline has been accomplished through the highly stereoselective introduction of a reverse prenyl group to create a quaternary carbon stereocenter using (−)-3a-hydroxyfuroindoline as a building block, construction of the indoline spiroaminal via cautious stepwise oxidations with cyclizations from the indoline, assembly of (Z)-dehydrohistidine, and photoisomerization of unnatural (Z)-neoxaline to the natural (E)-neoxaline as the key steps.