Addition of carbon nucleophiles to substituted N-acyliminium ions. A stereoselective route to trans-fused decahydroquinoline systems

A stereoselective route to trans-fused 2-substituted decahydroquinoline hydrochloride 11 featuring the addition of allyl tri-n-butyltin to a disubstituted N-acyliminium ion derived from glutarimide, followed by ring-closing metathesis is described (seven steps, 13% overall yield from lactam 4).