Diastereoselective Synthesis of (±)--Subincanadine C.

Starting from indolylmaleimide, concise and efficient total synthesis of (±)--subincanadine C was described via stereoselective Wittig olefination, base-induced selective mono-prenylation, regioselective Grignard reaction, diastereoselective Pictet-Spengler cyclization, regioselective oxidative carbon-carbon double-bond cleavage, one-pot reductions, and intramolecular cyclization pathway. An attempted synthesis of (±)-subincanadine C via diastereoselective Grignard addition to the α,β-unsaturated γ-lactam or diastereoselective reduction of a carbon-carbon double bond also resulted in yet another route to (±)--subincanadine C.