Ruthenium-catalyzed stereoselective intramolecular carbenoid C-H insertion for β- and γ-lactam formations by decomposition of α-diazoacetamides

(Chemical Equation Presented) An operationally simple catalytic system based on [RuCl2(p-cymene)2] was developed for stereoselective cyclization of α-diazoacetamides by intramolecular carbenoid C-H insertion, and β-lactams were produced in excellent yields and >99% cis-stereoselectivity. The Ru-catalyzed reactions can be performed without the need for slow addition of diazo compounds and inert atmosphere. With α-diazoanilides as substrate, the carbenoid insertion was directed selectively to aromatic C-H bond leading to γ-lactam formation (>95% yield).