From Enantioenriched Donor‐Acceptor Cyclopropylcarbinols to Axially Chiral Arylnaphthalenes through Aryldihydronaphthalenes: Central‐to‐Axial Chirality Exchange

Abstract

AbstractTransformations of enantioenriched donor‐acceptor (D−A) cyclopropylcarbinols to enantioenriched 1‐arylnaphthalenes that bear anortho‐substituent on a benzene ring provided a successful chirality‐exchange method with a high level of stereoinduction. A central chirality‐transfer step, i. e., a Lewis‐acid‐mediated ring‐opening cyclization of enantioenriched D‐A cyclopropylcarbinols (97 to >99 % ee), afforded 1‐aryl‐1,2‐dihydronaphthalenes with anortho‐substituent (Me, Br, OMe, OBn, or OiPr) on the benzene ring with high enantioselectivity (97 to >99 % ee). The central‐to‐axial chirality‐exchange step, i. e., the dehydrogenation of the obtained enantioenriched 1‐aryl‐1,2‐dihydronaphthalenes using DDQ, furnished the axially chiral 1‐arylnaphthalenes with high enantioselectivity (90 to >99 % ee). Importantly, we developed a highly enantioselective synthesis of a 1‐arylnaphthalene with anortho‐alkoxy group on the benzene ring. Moreover, we improved the chirality exchange to furnish a 1‐arylnaphthalene with anortho‐alkoxy‐substituted benzene ring in high yield with high ee.