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。
Direct Asymmetric Aldol Reactions Inspired by Two Types of Natural Aldolases: Water-Compatible Organocatalysts and Zn<sup>II</sup> Complexes
water-compatible amino-acid-based catalysts was explored in the development of diastereo- and enantioselectivedirectaldolreactions of a broad range of substrates. Chiral C2-symmetrical proline- and valine-based amides and their ZnII complexes were designed for use as efficient and flexible chiral catalysts for enantioselectivealdolreactions in water, on water, and in the presence of water. The presence of
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