Preparation of enantiopure sultams by intramolecular Diels–Alder reaction of furan-containing vinylsulfonamides
摘要:
Enantiomerically pure delta- and gamma-sultams have been prepared by intramolecular [4+2] cycloaddition of N-1-phenylethyl substituted vinylsulforiamides with purely thermal activation and under high pressure, An optimized procedure for reductive debenzylation of the resultant delta-sultams is also reported. (C) 2002 Elsevier Science Ltd. All rights reserved.
Asymmetric Imine Hydroboration Catalyzed by Chiral Diazaphospholenes
作者:Matt R. Adams、Chieh-Hung Tien、Robert McDonald、Alexander W. H. Speed
DOI:10.1002/anie.201709926
日期:2017.12.22
first use of diazaphospholenes as chiral catalysts has been demonstrated with enantioselective iminehydroboration. A chiral diazaphospholene prepared in a simple three‐step synthesis from commercial materials has been shown to achieve the highest enantioselectivity for the hydroboration of alkyl imines with pinacolborane reported to date. Enantiomer ratios of up to 88:12 were obtained with low (2 mol %)
New Potentially Chelating Chiral Magnesium Amide Bases for Use in Enantioselective Deprotonation Reactions
作者:William Kerr、Michael Middleditch、Allan Watson
DOI:10.1055/s-0030-1259282
日期:2011.1
to prepare novel chiral magnesium bisamide reagents. These amide bases were subsequently applied within asymmetric deprotonation reactions to probe the potential for chelation-assisted selectivity enhancement. Good levels of selectivity could be achieved (up to 87:13 e.r. (R:S)) across a range of prochiral cyclohexanone substrates when employing a thiophene-derived magnesium bisamide complex.
合成了一系列手性仲胺,结合了 5 或 6 元杂环,并用于制备新型手性镁双酰胺试剂。随后将这些酰胺碱应用于不对称去质子化反应中,以探索螯合辅助选择性增强的潜力。当使用噻吩衍生的镁双酰胺复合物时,可以在一系列前手性环己酮底物上实现良好的选择性(高达 87:13 er (R:S))。
Scope of the organocatalysed asymmetric reductive amination of ketones with trichlorosilane
作者:François-Moana Gautier、Simon Jones、Xianfu Li、Stephen J. Martin
DOI:10.1039/c1ob05965c
日期:——
A highly active organocatalyst has been shown to affect the asymmetric reductive amination of ketones producing both aromatic and aliphatic amines. At 1 mol% catalyst loading, a series of structurally diverse chiral amines were quickly and economically prepared with good enantioselectivity and generally useful yield. The efficient synthesis of the calcimimetic (+)-NPS R-568 (67%, 89% ee) demonstrated the synthetic applicability of this methodology.
A series of chiral vicinal tertiary diacylamides with C-2-symmetry was synthesized from (S)-alpha-phenylethylamine, different aromatic aldehydes, and oxalyl chloride. The diacylamides obtained were then reduced to afford chiral vicinal diamines with C-2-symmetry. We propose that the diacylamides existed in four stable conformational isomers in solution because of the dihedral angle between acylamide bonds.
Asymmetric synthesis of methyl N-(1-phenylethyl)-3-aza-10-oxatricyclo[5.2.1.01,5]-4-oxo dec-8-en-6-carboxylate by an intramolecular Diels-Alder reaction
作者:J Zylber、A Tubul、P Brun
DOI:10.1016/0957-4166(95)00018-k
日期:1995.2
The title compound can be obtained with up to five asymmetric centres of known absolute configuration by a diastereoselective intramolecular Diels-Alder reaction between optically active N-substituted furfurylamines and maleic anhydride, in which the chirality is transferred from one stereocentre to the four others.