A unified strategy for the synthesis of (-)-maoecrystal Z, (-)-trichorabdal A, and (-)-longikaurin E

Herein we describe in full our investigations that led to the completion of the first total syntheses of (-)-maoecrystal Z, (-)-trichorabdal A, and (-)-longikaurin E. The unified strategy employs a Ti-III-mediated reductive epoxide coupling to rapidly prepare a key spirolactone. Highly diastereoselective Sm(II-)mediated reductive cyclizations and a Pd-II-mediated oxidative cyclization enable the construction of three architecturally distinct ent-kauranoid frameworks from this common intermediate. (C) 2014 Elsevier Ltd. All rights reserved.