Synthesis of chiral trans-fused pyrano[3,2-c][2]benzoxocines from d-mannose by regioselective 8-endo-aryl radical cyclization

A simple chiral synthesis of trans-pyrano[3,2-c][2]benzoxocines 8a–d in good yields (60–75%) through regioselective 8-endo-trig aryl radical cyclization of the d-mannose derived enopyranosides 7a–d with Bu3SnH is described.