'Abnormal' eight-membered ring formation through S(N)2' intramolecular Nozaki/Kishi reaction in a synthetic approach to a taxane precursor

Article abstract of DOI:10.1016/S0040-4039(97)10512-3

Two different reactions were experimented for the construction of the eight-membered B-ring of taxane skeleton through the formation of the C9-C10 bond. A SmI₂ promoted radical reaction on seco-alkynyl aldehydes 11cis or 11trans failed. A Nozaki/Kishi reaction carried out on the seco-iodovinyl aldehyde 12trans led, through an unprecedented intramolecular S(N)2' reaction, to the 'abnormally' cyclised product 14, the structure of which has been confirmed by X-ray crystalllography.