Asymmetric diels-alder reaction of new chiral acrylate derived from (S)-indoline 2-carboxylic acid with cyclopentadiene

Abstract

In order to control stereoselectivity in the asymmetric Diels-Alder reaction, a series of a new chiral acrylate have been synthesized from (S)-indoline 2-carboxylic acid. The chiral acrylates were examined in Diels-Alder reaction with cyclopentadine under various conditions such as Lewis acids and temperatures. When the chiral acrylate which have the steric hinderance of two bulky phenyl groups instead of acid moiety in indoline 2-carboxylic acid was reacted with cyclopentadiene under $Et_2AlCl$ catalyzed condition, the highest endo/exo ratio ($>99\%$) and almost quantitative diastereoface selectivity (endo-(R) configuration) was obtained. The Diels-Alder adduct was converted to (+)-(1R,2R,4R)-norbornene methanol and chiral auxiliary by the reductive cleavage with $LiAlH_4$.