Stereoselectivity in the Wittig reaction of phenyl 3-pyridyl ketones: Amide substituent effect on the preferential (E)-olefin formation

Article abstract of DOI:10.1016/S0040-4039(98)01194-0

A Wittig reaction of amide substituted phenyl 3-pyridyl ketones with 'nonstabilized' phosphorus ylides which contain a carboxyl terminus preferentially forms (E)-olefin. The preference for this stereoselectivity stems from either hydrogen bonding or salt-bridge formation between the amide group and the carboxyl terminus during the oxaphosphetane intermediate formation.