Rhodium‐Catalyzed Asymmetric Hydrohydrazonemethylation of Styrenes: Access to Chiral Hydrazones, Hydrazides, Hydrazines and Amines

Abstract The catalytic asymmetric hydroformylation of styrenes was combined with condensation the resulting aldehydes acetohydrazide as nucleophile leading to γ‐chiral N’‐substituted aceto‐hydrazones. This cascade reaction is called hydrohydrazonemethylation (HHM) in analogy similar hydroformylation/condensation sequences. catalyst formed situ from commercially available chiral phosphine‐ligand ( R , ) ‐ Ph‐BPE and [Rh(acac)(CO) 2 ] used at a loading 0.2 mol%. stable products are not prone tautomerization providing versatile intermediates. Their one‐pot reduction DMAB/TsOH resulted corresponding acetohydrazides (14 examples) yields ranging 73% 91% enantioselectivities 77% 97% ee . Deprotection led β‐chiral hydrazines. Reduction hydrogenolysis hydrazones over Raney‐Ni yielded primary amines 95% Diastereoselective functionalization C=N bond further synthetic option, demonstrated by allylation (allyl)SiCl 3 magnified image