REGIO- AND STEREO-CHEMICAL FEATURES OF THE STANNYLCOPPER(I)-INDUCED SUBSTITUTION IN PROPARGYLIC SUBSTRATES

Article abstract of DOI:10.1016/S0022-328X(00)98533-4

Stannylcopper(I) species, R3SnCu and 2CuLi, preferentially convert propargylic substrates, R¹C<*>CCR²R³X (X=Br, MeCO2, MeS(O)O or MeSO3) into allenes R3Sn(R¹)C=C=CR²R³.Only when the group R¹ causes much greater steric hindrance than with R² and R³ is the acetylenic product R¹C<*>CCR²R³SnR3 formed.The stereochemical course of the allene formation has been studied in both the steroid and non-steroid series, and found to be mainly or exclusively anti.