设计并合成了含有中心和平面手性元素的新型平面手性二茂铁亲核催化剂(Fc-PIP),用于仲醇的对映选择性酰基转移。鉴定出具有高选择性因子(高达 S = 1892)的非常有效的催化剂。比较中心手性和平面手性的组合揭示了对“匹配”手性元素的强烈要求,表明咪唑环的立体中心应与二茂铁片段位于同一面上;否则,催化剂完全失活。提出了一种完全堆叠的过渡态,它解释了仲醇动力学拆分的高选择性。尤其,
Nonenzymatic Dynamic Kinetic Resolution of Secondary Alcohols via Enantioselective Acylation: Synthetic and Mechanistic Studies
作者:Sarah Yunmi Lee、Jaclyn M. Murphy、Atsushi Ukai、Gregory C. Fu
DOI:10.1021/ja307425g
日期:2012.9.12
Because of the ubiquity of the secondary carbinol subunit, the development of new methods for its enantioselective synthesis remains an important ongoing challenge. In this report, we describe the first nonenzymatic method for the dynamic kinetic resolution (DKR) of secondaryalcohols (specifically, aryl alkyl carbinols) through enantioselectiveacylation, and we substantially expand the scope of this
由于二级甲醇亚基的普遍存在,开发其对映选择性合成的新方法仍然是一个重要的持续挑战。在本报告中,我们描述了通过对映选择性酰化对仲醇(特别是芳烷基甲醇)进行动态动力学拆分 (DKR) 的第一种非酶促方法,并且我们大大扩展了这种方法的范围,与酶促反应相比。简单地将醇的动力学拆分的有效方法与醇的外消旋化的活性催化剂相结合不会导致 DKR,因为钌基外消旋化催化剂与其中使用的酰化剂 (Ac(2)O) 不相容。动力学分辨率。机理研究表明,钌催化剂通过形成稳定的乙酸钌络合物而失活;this deleterious pathway was circumvented through the appropriate choice of acylating agent (an acyl carbonate). 这种新工艺的机理研究表明亲核催化剂的可逆 N-酰化,从催化剂到醇的酰基转移作为速率决定步骤,并且碳酸根阴
Enantioselective acyl transfer catalysts and their use in kinetic resolution of alcohols and desymmetrization of meso-diols
申请人:Birman Vladimir
公开号:US20050256150A1
公开(公告)日:2005-11-17
Novel enantioselective acylation catalysts comprising chiral derivatives of DHIP and DHIQ, having the following representative general structures are disclosed:
These new compounds are useful for resolving racemates or further enhancing the enantiomeric excess of an enantiomerically enriched composition and for desymmetrizing meso compounds.
2,3-Dihydroimidazo[1,2-a]pyridines: A New Class of Enantioselective Acyl Transfer Catalysts and Their Use in Kinetic Resolution of Alcohols
作者:Vladimir B. Birman、Eric W. Uffman、Hui Jiang、Ximin Li、Corey J. Kilbane
DOI:10.1021/ja0491477
日期:2004.10.1
unexplored 2,3-dihydroimidazo[1,2-a]pyridine (DHIP) has been shown to be a competent acyl transfer catalyst. Its chiral 2-phenyl derivatives obtainable in two steps from commercially available starting materials have proved to be effective acylation catalysts, giving high levels of enantioselectivity (s = 20-85) in kineticresolution of secondary benzylic alcohols. A transition state model explaining
Obtaining Enriched Compounds via a Tandem Enantioselective Reaction and Kinetic Resolution Polishing Sequence
作者:Maggie I. Klauck、Sachin G. Patel、Sheryl L. Wiskur
DOI:10.1021/jo202653b
日期:2012.4.6
tandem method of coupling an enantioselective reaction with a nonenzymatic kinetic resolution to prepare highly enantioenriched compounds. The procedure employs a moderately selective enantioselective reaction on a ketone or aldehyde to form an enriched alcohol followed by a kinetic resolution of the alcohol to generate ee’s of >99% in yields greater than what is possible with a kinetic resolution. This
3-Acyloxypyridines and 4-acetyl-1,2,4-triazole were found to react enantioselectively with (RS)-1-phenylethanol to give (R)-1-phenethyl carboxylates in high purity, catalyzed by lipase P (from Pseudomonas fluorescens).