Synthesis of 4-substituted chromanes and 1-substituted benzo[f]chromanes by tandem 6-exo trig cyclization-SRN1 reactions.

J. I. BARDAGÍ, S. E. VAILLARD, R. A. ROSSI,

Arkivoc

Año: 2007 vol. IV p. 73 - 83

1424-6376

4-Substituted chromanes and 4-substituted benzo[ f]chromanes are obtained in good yields by photostimulated S(RN)1 reactions of aryl halides ortho-substituted with butenyloxy groups with -SnMe3, -PPh2 and -CH2NO2 ions as nucleophiles. The synthetic strategy involves the versatile application of a 6-exo trig radical ring closure in the propagation cycle of the SRN1 reaction. The factors governing the observed distribution of substitution products are also discussed