Diastereoselective Synthesis of (±)-<i>epi</i>-Subincanadine C

Starting from indolylmaleimide,
concise and efficient total synthesis
of (±)-epi-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 (±)-epi-subincanadine C.