syn-Selective Catalytic Asymmetric Nitro-Mannich Reactions Using a Heterobimetallic Cu−Sm−Schiff Base Complex
摘要:
syn-Selective catalytic asymmetric nitro-Mannich reactions using a heterobimetallic Cu/Sm/Schiff base complex are described. The present method is complementary to the previously reported methods, and products were obtained in high syn-selectivity (> 20:1), yield (99-62%), and enantioselectivity (98-83% ee). Both Cu and Sm metals, aligned suitably in a dinucleating Schiff base ligand, were essential to realize high synselectivity.
A Three-Component Reaction for the One-Pot Preparation of
β-Amino-α,α-Difluoroketones from Trimethyl(trifluoromethyl)silane (CF3TMS), Acylsilanes and Imines
the acylsilane compared to the imine allows the direct mixing of all the reagents in a three-component, one-pot process. A methodology allowing the direct preparation of β-amino-α,α-difluoroketones from the Ruppert–Prakash reagent (CF3TMS), acyltrimethylsilanes and N-Boc or N-(diphenylphosphinyl)imines is reported. The process, initiated by a catalytic amount of tetra-n-butylammonium difluorotriphenylsilicate
The Mannich Reaction of Malonates with Simple Imines Catalyzed by Bifunctional Cinchona Alkaloids: Enantioselective Synthesis of β-Amino Acids
作者:Jun Song、Yi Wang、Li Deng
DOI:10.1021/ja060716f
日期:2006.5.1
efficient, direct asymmetric Mannichreactions with malonates and N-Boc aryl and alkyl imines by cooperative hydrogen-bonding catalysis with a cinchona alkaloid bearing a thiourea functionality. We have also extended the scope of this reaction to beta-ketoesters. The synthetic value of this new reaction is demonstrated in the establishment of a convergent enantioselective route toward the biologically
Direct Catalytic Asymmetric Mannich-type Reaction of Hydroxyketone Using a Et<sub>2</sub>Zn/Linked-BINOL Complex: Synthesis of Either <i>a</i><i>nti</i>- or <i>s</i><i>yn</i>-β-Amino Alcohols
Full details of a direct catalyticasymmetric Mannich-type reaction of a hydroxyketone using a Et2Zn/(S,S)-linked-BINOL complex are described. By choosing the proper protective groups on imine nitrogen, either anti- or syn-beta-amino alcohol was obtained in good diastereomeric ratio, yield, and excellent enantiomeric excess using the same zinc catalysis. N-Diphenylphosphinoyl (Dpp) imine 3 gave anti-beta-amino
first catalytic addition reactions of sulfonylimidates have been accomplished. In the presence of a catalytic amount of DBU (normally 5−10 mol %), sulfonylimidates reacted with several N-protected imines, methyl acrylate, and azodicarboxylate to afford the corresponding addition adducts, sulfonylimidates, in excellent yields. In the addition reactions to imines, high anti-selectivity was observed. A
磺酰亚胺酯的第一次催化加成反应已经完成。在催化量的 DBU(通常为 5-10 mol%)存在下,磺酰亚胺酯与几种 N 保护的亚胺、丙烯酸甲酯和偶氮二羧酸酯反应,以极好的收率提供相应的加合物磺酰亚胺酯。在与亚胺的加成反应中,观察到高抗选择性。还描述了从醛和磺酰亚胺酸酯直接形成 β-氨基酸衍生物的新方法。
Organocatalytic Enantioselective Mannich-Type Reaction of Phosphorus Ylides: Synthesis of Chiral <i>N</i>-Boc-β-Amino-α-methylene Carboxylic Esters
The first asymmetric Mannich-type reaction of stabilized phosphorus ylides and N-Boc aldimines was described promoted by a readily available and recyclable chiral bisthiourea organocatalyst. Subsequent reaction with formalin smoothly provides N-Boc-β-amino-α-methylene carboxylic esters in a highlyenantiomericallyenriched form (up to 96% ee).