文摘
A concise total synthesis of przewalskin B was accomplished from readily available diene 7. Key features of the synthesis involved a Diels鈥揂lder reaction to install the A ring, a Claisen鈥揓ohnson rearrangement to establish the spiro-quaternary center, and a ring-closing metathesis (RCM) of a sterically crowded system to construct the cyclic enone moiety.