A catalytic asymmetric total synthesis of (−)-perophoramidine. Issue 1 (22nd August 2014) - Trost, B. M.
Abstract : We describe a catalytic asymmetric total synthesis of the ascidian alkaloid (−)-perophoramidine employing a Mo-catalyzed asymmetric allylic alkylation and unprecedented imino ether allylation as key steps. Abstract : We report a catalytic asymmetric total synthesis of the ascidian natural product perophoramidine. The synthesis employs a molybdenum-catalyzed asymmetric allylic alkylation of an oxindole nucleophile and a monosubstituted allylic electrophile as a key asymmetric step. The enantioenriched oxindole product from this transformation contains vicinal quaternary and tertiary stereocenters, and is obtained in high yield along with high levels of regio-, diastereo-, and enantioselectivity. To install the second quaternary stereocenter in the target, the route utilizes a novel regio- and diastereoselective allylation of a cyclic imino ether to deliver an allylated imino ether product in near quantitative yield and with complete regio- and diastereocontrol. Oxidative cleavage and reductive amination are used as final steps to access the natural product.