A Bench-Stable Homodinuclear Ni<sub>2</sub>−Schiff Base Complex for Catalytic Asymmetric Synthesis of α-Tetrasubstituted <i>anti</i>-α,β-Diamino Acid Surrogates
Catalyticasymmetric direct Mannich-type reactions of α-substituted nitroacetates using a new bench-stable homodinuclear Ni2−Schiff base 1b complex are described. The Ni2−1b complex gave Mannich products, precursors for anti-α,β-diamino acids with an α-tetrasubstituted carbon stereocenter, in >99−91% ee. The Ni2−1b complex was also applicable to direct Mannich-type reactions of malonates and β-keto
Enantioselective Aza-Henry Reaction with an <i>N</i>-Sulfinyl Urea Organocatalyst
作者:MaryAnn T. Robak、Monica Trincado、Jonathan A. Ellman
DOI:10.1021/ja075653v
日期:2007.12.1
simultaneously acidify the urea and provide asymmetric induction in hydrogen-bond-catalyzed reactions. The utility of this new catalyst structure is demonstrated by the high selectivity provided in the aza-Henryreaction not only for aromatic N-Boc imine substrates but also for aliphatic imines for which enantioselective H-bonding catalysis has not previously been demonstrated.
An expeditious one-pot synthesis of diethyl N-Boc-1-aminoalkylphosphonates
作者:Anna Klepacz、Andrzej Zwierzak
DOI:10.1016/s0040-4039(01)02289-4
日期:2002.2
A general one-pot, purification-free synthesis of diethyl N-Boc-1-aminoalkylphosphonates has been developed. The procedure involves base-catalyzed Michael-type addition of sodium diethyl phosphite to N-Boc imines generated in situ by the action of sodium hydride on α-amidoalkyl-p-tolyl sulfones in tetrahydrofuran.