Asymmetric Synthesis of Primary Amines by Nucleophilic Addition of Alkyllithium Compounds to Aldehyde SAMP/RAMP Hydrazones

The aldehydes 1 or 5 are converted to the SAMP hydrazones 2 or the α‐alkylated SAMP hydrazones 7 and treated with organolithium compounds at low temperature. Cleavage of the NN bond of the resulting hydrazines 3 and 8 with Raney‐Ni/H2, or of the N‐methoxycarbonylhydrazines 9 with Li/NH3, yield the amines 4 with 61–90% ee, the amines 11 with 45–96% de and 93 → 99% ee. The absolute configuration of the amines 11 was established by X‐ray analysis of an appropriate MTPA derivative.