Regioselective allylmetalation of allenes with tetraallylmanganate or allylmagnesium chloride under MnCl2 catalysis

Treatment of allenes with tetraallylmanganate provides allylated products with high regioselectivity. A catalytic amount of MnCl2 combined with allylmagnesium chloride also achieves efficient allylmetalation of allenes. The resulting alkenylmagnesium species react with various electrophiles. In the presence of molecular oxygen, the alkenyl magnesium undergoes diallylation reaction. A cyclization reaction of 1,2,6-heptatriene with tetraallylmanganate is also described.