Platinum-catalyzed tandem diboration/intramolecular allylboration: Diastereoselective access to cyclohexanes bearing 1,3-diols

A tandem reaction sequence consisting of platinum-catalyzed diboration of 1,3-dienes followed by intramolecular allylboration and oxidative hydrolysis has been developed for constructing cyclic structures that bear a 1,3-diol. This methodology has proven effective for synthesizing cyclohexanes from dienals in good yields (44-64%) to generate diols containing two new vicinal stereocenters, one of which is quaternary. The products are obtained in high regio- and diastereomeric ratios (>19:1). A preexisting stereocenter on the substrate can provide high levels of asymmetric induction in the product.