IntramolecularDiels-Alderreaction of l-azadienes was conducted by heating the α,β-unsaturated amides (2a ∼ d and 6) in the presence of trimethyl- chlorosilane, triethylamine and zinc chloride to give benzo- and indolo[a]- quinolizidines (5a ∼ e and 7).
A versatile and stereocontrolled synthesis of quinolizidines and indolizidines using trialkylsilyl trifluoromethanesulphonate: total synthesis of (±)-tylophorine
Quinolizidines and indolizidines were synthesised by reaction of α,β-unsaturated enamide esters with trialkylsilyltrifluoromethanesulphonate and triethylamine in dichloromethane; a short totalsynthesis of (±)-tylophorine (16) was achieved via annelation.