Transition metal catalyzed cycloaddition reactions of chiral ketimines with alkenes and carbon monoxide: reaction conditions, substrate variations and stereoselectivity

Abstract

Abstract The three component reaction of chiral N,N′-bis(aryl)tetrahydropyrrolo-[2,1-c][1,4]oxazine-3,4-diylidenediamines with carbon monoxide and terminal alkenes produces spiro lactams by a formal [2+2+1] cycloaddition reaction. The constitution of one of the tricyclic products is confirmed by X-ray analysis revealing the complete regioslectivity of the reaction since only the imine moiety next to the oxazine oxygen atom is transformed during the catalysis whereas the second imine function shows no reactivity at all. Terminal alkenes react quantitatively if Ru3(CO)12 is used as the catalyst precursor but the catalysis also works catalytically if Fe2(CO)9 is employed. The Ru3(CO)12 amount may be lowered to 0.5 mol%. Internal alkenes and acrylic acid methyl ester give the desired spiro lactams under analogous reaction conditions in very poor yields.