A new type of C(2)-symmetric chiral bisguanidine was designed as a highly efficient catalyst in the inverse-electron-demandhetero-Diels-Alderreaction of chalcones with azlactones for the first time. A wide variety of gamma,delta-unsaturated delta-lactone derivatives with alpha-quaternary-beta-tertiary stereocenters were obtained in high yields (up to 88%) with excellent enantioselectivities (up to
Application of Proline-Functionalised 1,2-Diphenylethane-1,2-diamine (DPEN) in Asymmetric Transfer Hydrogenation of Ketones
作者:Charles V. Manville、Gordon Docherty、Ranbir Padda、Martin Wills
DOI:10.1002/ejoc.201101164
日期:2011.12
A series of enantiomerically pure ligands containing a combination of proline and DPEN groups have been prepared and employed in the asymmetrictransferhydrogenation of ketones. In the case of cyclic ketones, alcohols with ee values of up to 98 % were obtained.
一系列包含脯氨酸和 DPEN 基团组合的对映体纯配体已被制备并用于酮的不对称转移氢化。在环酮的情况下,获得了 ee 值高达 98% 的醇。
Chiral Bisformamides as Effective Organocatalysts for the Asymmetric One-Pot, Three-Component Strecker Reaction
bisformamides have been shown to catalyze the asymmetric one-pot, three-component Streckerreaction, which produced the α-amino nitriles in excellent yields (up to 99%) with good enantioselectivities (up to 86% ee). Optically pure products could be obtained after a single recrystallization. A possible transition state (TS1) has been proposed to explain the origin of asymmetric inductivity and reactivity according
C 2对称的手性双甲酰胺已显示出催化不对称的一锅,三组分Strecker反应,该反应以优异的对映体选择性(高达86%ee)以优异的收率(高达99%)产生了α-氨基腈。在单次重结晶后可获得光学纯的产物。根据在B3LYP / 6-31G(d)水平下优化的催化剂2a的几何形状和产物4a的绝对构型,已经提出了一种可能的过渡态(TS 1)来解释不对称感应性和反应性的起源。
<i>C</i><sub>2</sub>-Symmetric Bisprolinamide as a Highly Efficient Catalyst for Direct Aldol Reaction
[reaction: see text] The catalytic activity of the prolinamide-type catalysts may be improved by introducing additional prolinamide moiety into the catalyst, while the enantioselectivity can still be maintained or further improved. A C2-symmetric bisprolinamide with two prolinamide moieties has been found to be an excellent catalyst for directaldolreaction with more than doubled reactivity and better