An asymmetrichydrogenation of hydrazones with a unique nickel catalyst has been developed for the synthesis of chiral hydrazines with up to 99 % yield and 99.4 : 0.6 er and a broad substrate scope. Deuterium labelling experiments indicated that the hydrazone substrates undergo imine-enamine tautomerization in the mixed solvents.
Highly Enantioselective Radical Addition to <i>N</i>-Benzoyl Hydrazones Using Chiral Ammonium Salts
作者:Doo Ok Jang、Sang Yoon Kim
DOI:10.1021/ja807685r
日期:2008.12.3
In the presence of a protonated cinchonine derivative, radicaladdition reactions proceeded efficiently, affording addition adducts in high yields with an extremely high enantioselectivity. The chiralammonium salt was recyclable after a simple aqueous workup. The reaction provides environmentally benign reaction conditions.