Direct organocatalytic asymmetric Mannich-type reactions in aqueous media: one-pot Mannich-allylation reactions
作者:Armando Córdova、Carlos F Barbas
DOI:10.1016/s0040-4039(03)00019-4
日期:2003.2
organocatalytic asymmetric Mannich-type reactions in aqueousmedia are demonstrated herein. l-Proline-catalyzed reactions in aqueousmedia to provide β-formyl substituted α-amino acid derivatives with excellent diastereoselectivities (dr up to 19:1, syn/anti) and high enantioselectivities (ee between 72 and >99%). These conditions provided for the development of novel one-potasymmetric syntheses of cyclic
A Designer Axially Chiral Amino Sulfonamide as an Efficient Organocatalyst for Direct Asymmetric<i>anti</i>-Selective Mannich Reactions and<i>syn</i>-Selective Cross-Aldol Reactions
作者:Taichi Kano、Yukako Yamaguchi、Keiji Maruoka
DOI:10.1002/chem.200900267
日期:2009.7.6
Aminosulfonamide catalyst: A distal proton of the axiallychiralaminosulfonamide (S)‐1 realized the opposite diastereoselectivity in Mannich and cross‐aldol reactions compared with that observed in proline‐catalyzedreactions. The reactionscatalyzed by (S)‐1 proceeded smoothly to give the anti‐Mannich and syn‐aldol adducts in excellent enantioselectivity (see scheme).
One-Pot Asymmetric Synthesis of β-Cyanohydroxymethyl α-Amino Acid Derivatives: Formation of Three Contiguous Stereogenic Centers
作者:Shin-ichi Watanabe、Armando Córdova、Fujie Tanaka、Carlos F. Barbas
DOI:10.1021/ol027048x
日期:2002.12.1
[reaction: see text] One-pot asymmetric Mannich-hydrocyanation reactions are described. Reaction of unmodified aldehydes with N-PMP-protected alpha-imino ethyl glyoxylate in the presence of catalyticamounts of L-proline followed by the addition of Et(2)AlCN provided highly enantiomericallypure beta-cyanohydroxymethyl alpha-amino acid derivatives possessing three contiguous stereogenic centers as
List–Barbas–Mannich Reaction Catalyzed by Modularly Designed Organocatalysts
作者:Sandun Perera、Debarshi Sinha、Nirmal K. Rana、Van Trieu-Do、John Cong-Gui Zhao
DOI:10.1021/jo4019304
日期:2013.11.1
The List-Barbas-Mannich reaction of ethyl (p-methoxyphenylimino)acetate (p-methoxyphenyl = PMP) with unmodified aldehydes or ketones catalyzed by modularly designed organocatalysts (MDOs) that are self-assembled from proline and cinchona alkaloid thioureas (such as a quinidine-derived thiourea) produces the corresponding gamma-oxo-alpha-amino acid derivatives in high yields and excellent stereoselectivities. No solvent is necessary for this reaction. Aldehydes are especially good substrates for this reaction: The reaction takes only a few minutes to yield the corresponding List-Barbas-Mannich products in excellent dr (up to >99:1) and ee values (up to >99% ee).