Triorganoindium reagents in cross-coupling reactionstransition-metal-free reactions with benzopyranyl acetals and tetrahydroisoquinolines and solid-stable organometallics

Abstract

This Thesis presents the development of a new transition-metal-free coupling reaction of triorganoindium reagents with chromene and isochroman acetals under BF3·OEt2 activation. This reaction allows the synthesis of the corresponding 2-substituted 2H-chromenes and 1-substituted isochromans in good yields, in which aryl, heteroaryl, alkynyl, alkenyl, and alkyl groups can be transferred using only 50 mol% of the triorganoindium reagents. As an extension of this methodology, a transition-metal-free coupling reaction of triorganoindium reagents with N-protected tetrahydroisoquinolines (THIQs) under oxidative conditions is presented as well, where different aryl, heteroaryl, alkynyl, benzyl, and alkyl groups can be installed at the C-1 position of the THIQs, using only 50 mol% of the triorganoindium reagent. To demonstrate the synthetic utility of this reaction, it was applied to the synthesis of alkaloid Nuciferine. This Thesis also presents the synthesis and isolation of solid, bench-stable triorganoindium reagents by coordination with 4-dimethylaminopyridine (DMAP). Different R3In·DMAP complexes bearing aryl, heteroaryl, alkynyl, and benzyl groups were prepared and then used in palladium-catalyzed cross-coupling reactions, where they reacted efficiently with diverse electrophiles including aryl, alkenyl, allyl, and benzyl bromides.