Evidence for synclinal transition state in the reactions of aromatic aldehydes with α-(alkoxy)allylstannanes

Article abstract of DOI:10.1016/S0040-4020(01)88299-5

Unlike aliphatic aldehydes, aromatic aldehydes produce greater than 95% of syn-(Z) enol ether when treated with α-(alkoxy)allylstannanes in the presence of BF₃·Et₂O. However, in the presence of TiCl₄, the reaction of p-chloro-o-methoxybenzaldehyde with α-(alkoxy)crotylstannane produced predominantly the syn-(E) isomer.