Synthesis of novel cyclic α-amino acid derivatives via a one-pot sequential Petasis reaction/palladium catalysed process

A novel one pot Petasis reaction/palladium catalysed process is described involving 2-iodo/bromo benzylamine, ethyl glyoxalate and aryl/heteroaryl boronic acids. The in situ generated carbinolamine/imine undergoes the Petasis reaction to afford 2 which reacts with carbon monoxide or allene (1 atm) in the presence of Pd(0) to generate acyl palladium or π-allyl palladium species which are intercepted intramolecularly by the proximal secondary amine to afford isoindolone/4-methylene-3,4-dihydroisoquinoline α-amino acid derivatives in good yield.