New synthesis of 1,1-substituted hydrazines by alkylation of N-acyl- or N-alkyloxycarbonylaminophthalimide using the Mitsunobu protocol

N-acyl- and N-alkoxycarbonylaminophthalimides are prepared using a convenient reaction and are efficiently used as acid partners in Mitsunobu reaction. This reaction allows them to be alkylated by primary, secondary or benzyl groups. Comparison of the reactivities and pK(a) values of these N-substituted aminophthalimides suggest that the success of the Mitsunobu reaction in this case seems to be governed more by steric than by electronic effects. A final dephthaloylation step results in an efficient method for the preparation of 1,1-substituted hydrazines.