Ytterbium(III) triflate-catalyzed electrophilic cyclization of glyoxalate-derived unsaturated imines

Ytterbium(III) triflate was found to catalyze the electrophilic cyclization of some glyoxalate-derived unsaturated imines. The cyclization reactions gave exclusively fused amino γ-lactone products with good stereoselectivity. Moreover, a solid-phase version of the lanthanide-catalyzed reaction featured a lactonization with simultaneous cleavage of the product from the solid support.