New optically active amido-phosphinite ligand and ruthenium complexes
摘要:
The hydrogenation of acetoacetanilide in the presence of optically active ruthenium catalysts leads to 3-hydroxy-N-phenylbutanamide in good yield anti high enantioselectivity (ee>95%). Its direct phosphinylation with chlorodiphenylphosphine affords a new bifunctional amido-phosphinite ligand that can easily be coordinated to [(arene)RuCl2] and to the CpRuCl(PPh3) moiety with very good stereoselectivity from CpRuCl(PPh3)(2). (C) 1998 Elsevier Science Ltd. All rights reserved.
Catalytic Asymmetric Aldol-Type Reaction of Zinc Enolate Equivalent of Amides
作者:Ryosuke Haraguchi、Seijiro Matsubara
DOI:10.1021/ol401425s
日期:2013.7.5
Treatment of phenyl isocyanate with bis(iodozincio)methane gave a zinciomethylenated product, which acts as an amide-enoate equivalent. It did not react with an aldehyde efficiently, but gave the corresponding adduct in good yield in the presence of an aminoalcohol. Use of a catalytic amount of chiral aminoalcohol led the process to the catalytic asymmetric Aldol-type reaction.
Preparation of the Zinc Enolate Equivalent of Amides by Zinciomethylation of Isocyanates: Catalytic Asymmetric Reformatsky-Type Reaction
作者:Seijiro Matsubara、Ryosuke Haraguchi
DOI:10.1055/s-0034-1378514
日期:——
an activator, leads to a catalytic asymmetric Reformatsky-type reaction. Bis(iodozincio)methane [CH2(ZnI)2] transforms isocyanates (R–N=C=O) into the enolate equivalent of amides via zinciomethylation. The reactivity of the enolate equivalent as a nucleophile toward aldehydes depends on the R group of the isocyanate. For the enolate equivalent formed from phenyl isocyanate, the addition of a catalytic
摘要 双(碘并甲烷)甲烷[CH 2(ZnI)2 ]通过锌甲基化将异氰酸酯(RN = C = O)转化为酰胺的烯醇式当量。作为亲核体的烯醇化物等效物对醛的反应性取决于异氰酸酯的R基团。对于由异氰酸苯酯形成的烯醇盐当量,加入催化量的光学活性氨基醇(作为活化剂)会导致催化不对称的Reformatsky型反应。 双(碘并甲烷)甲烷[CH 2(ZnI)2 ]通过锌甲基化将异氰酸酯(RN = C = O)转化为酰胺的烯醇式当量。作为亲核体的烯醇化物等效物对醛的反应性取决于异氰酸酯的R基团。对于由异氰酸苯酯形成的烯醇盐当量,加入催化量的光学活性氨基醇(作为活化剂)会导致催化不对称的Reformatsky型反应。
Yeast-Mediated Reduction of<i>N</i>-Substituted Acetoacetamides. Improvement of Conversion by Immobilization
N-Ethylacetoacetamide and acetoacetanilide were enantioselectively converted into the corresponding (S)-3-hydroxy compounds by alginate- or polyurethaneimmobilized bakers’ yeasts, while without immobilization the yield of the yeast-mediated reaction was very low.
Synthesis and Suzuki-Miyaura Cross-Coupling of Enantioenriched Secondary Potassium β-Trifluoroboratoamides: Catalytic, Asymmetric Conjugate Addition of Bisboronic Acid and Tetrakis(dimethylamino)diboron to α,β-Unsaturated Carbonyl Compounds
作者:Gary A. Molander、Steven R. Wisniewski、Mona Hosseini-Sarvari
DOI:10.1002/adsc.201300640
日期:2013.10.11
Enantioenriched potassium beta-trifluoroboratoamides have been synthesized via an asymmetric, copper-catalyzed 1,4-addition of tetrahydroxydiboron (BBA) and tetrakis(dimethylamino)diboron to alpha,beta-unsaturated amides. These dibora reagents provide access to the desired organotrifluoroborates using effective and atom economical sources of boron. The copper-catalyzed beta-boration is extended to
Kinetic resolution of 3-hydroxyalkanamides with good to high selectivities was achieved by benzoylation using copper(II) triflate and (R,R)-PhBox [2,2′-isopropylidenebis(4-phenyl-2-oxazoline)] as catalyst, which also mediated enantioselective tosylation of 2,2-bis(hydroxymethyl)alkanamides with high efficiency.