The use of formaldehyde N,N-dialkylhydrazones as neutral Cl-nucleophiles in the iridium catalyzed substitution of allylic carbonates is described for two processes Kinetic resolution or, alternatively, stereospecific Substitution affords configurationally stable alpha,alpha-disubstituted aldehyde hydrazones in enantiomeric excess and yield. This umpolung approach allows for the construction of optically active allylic nitrile and dithiolanes as well as branched alpha-aryl aldehydes. A catalyst controlled reaction with Enders chiral hydrazone :derivatives followed by diastereoselective nucleophilic addition to the :hydrazone products. constitutes a two-step stereo divergent synthesis of chiral amines.