Iterative Catalyst-Controlled Diastereoselective Matteson Homologations Enable the Selective Synthesis of Benzestrol Isomers.

We report the development of an iterative Matteson homologation reaction with catalyst-controlled diastereoselectivity through the design of a new catalyst. This reaction was applied to the selective synthesis of each stereoisomer of benzestrol, a bioactive compound with estrogenic activity featuring three contiguous stereocenters. The different stereoisomers were assayed to determine their binding affinity for the estrogen receptor α (ERα), and the absolute configuration of the compound having uniquely high activity was determined.

High Prevalence of Gastric Preneoplastic Lesions in East Asians and Hispanics in the USA.

Background: The prevalence of H. pylori infection and the incidence of gastric cancer differ widely around the world, but it is unclear whether these differences are mirrored in the multiethnic population of the USA.

Aims: This study tested the hypothesis that the prevalence of both H.