Application of 7-endo, 8-endo and 9-endo radical cyclisations to the synthesis of conformationally constrained amino acids and comparison with the corresponding Heck reactions

Abstract

Radical cyclisation of substrates 1a–c proceeds smoothly to give seven-, eight- and nine-membered rings 3a–c in 73, 71 and 52% yield respectively; comparison of these results with those obtained using the intramolecular Heck reactions suggests that the two cyclisation methods provide complementary approaches to medium-sized rings.