Total Synthesis of Sophoraflavanone H and Confirmation of Its Absolute Configuration

Abstract

Sophoraflavanone H (1) is a polyphenol with a hybrid-type structure containing 2,3-diaryl-2,3-dihydrobenzofuran and flavanone ring moieties. This compound and related analogues are promising leads for antimicrobial and antitumor drug development. Here we describe a total synthesis of 1 and its diastereomer. The dihydrobenzofuran and flavanone rings were constructed by a Rh-catalyzed asymmetric C–H insertion reaction and selective oxy-Michael reaction. The absolute configuration of 1 was established by X-ray crystallographic analysis and CD spectral investigation of synthetic derivatives.

Catalytic asymmetric carbenoid α-C–H insertion of ether

“…Interestingly, the enantioselectivity of the dihydrobenzofuran 26 could be enhanced by introducing a methyl ether, albeit the removal of which posed challenges ( Scheme 6 ). 24 …”