Cobalt-catalysed (4+3)-annulation of oxiranes with 4-vinyl indoles: stereospecific access to fused oxepinoindoles

A cobalt( ii )-catalyzed (4+3)-annulation of oxiranes with 4-vinyl indoles has been accomplished to furnish oxepino[ c , d ]indoles. The use of cobalt-catalysis, stereoselectivity and chirality transfer are the important practical features.