Studies on the asymmetric cycloaddition of 2-azaallyl anions with alkenes

A preliminary survey of strategies for the asymmetric cycloaddition of nonstabilized 2-azaallyllithiums with alkenes is reported. The chiral diamine (−)-sparteine exerted little, if any, absolute stereocontrol. The attachment of a chiral auxiliary to the anion was more successful, leading to the first example of an asymmetric cycloaddition of a 2-azaallyllithium (24 to 25, 98% e.e.).