On the stereoselective bicyclization of aminodienes catalyzed by chelating diamide complexes of the group 3 metals. A direct comparison of Sc(iii) and Y(iii) bis(amide)s with an application to the synthesis of alkaloid 195F
Oximes possessing γ-, δ or ω-alkenyl substituents are cyclised by phenylselenyl bromide, or by phenylselenyl chloride and an appropriate silver salt to the corresponding cyclicnitrones; the seleno nitrones undergo facially specific cycloaddition reactions with N-methylmaleimide; bis(alk-γ,δ-enyl) ketones undergo regiospecific cyclisation and stereospecific intramolecular cycloaddition to furnish spirocyclic