Catalyzed acyl halidealdehyde cyclocondensations. New insights into the design of catalytic cross aldol reactions
作者:Scott G. Nelson、Zhonghui Wan、Timothy J. Peelen、Keith L. Spencer
DOI:10.1016/s0040-4039(99)01308-8
日期:1999.9
quantities (2.5–20 mol%) of Al(SbF6)3 catalyze the di(isopropyl)ethylamine-mediated cyclocondensation of various acylhalides and enolizable aldehydes to afford β-lactones in good yields (58–93%). These reactions are discussed as a strategy for executing chemo- and regiospecific catalyzed cross aldol reactions.
Catalytic Asymmetric Acyl Halide−Aldehyde Cyclocondensation Reactions of Substituted Ketenes
作者:Scott G. Nelson、Cheng Zhu、Xiaoqiang Shen
DOI:10.1021/ja0391208
日期:2004.1.1
Catalyticasymmetricacylhalide-aldehydecyclocondensation (AAC) reactions of alkyl-substituted ketenes with structurally diverse aldehydes provide cis-disubstituted beta-lactones with high enantioselectivity. The AAC reactions utilize a novel Al(III)-triamine catalyst in which the metal's dynamic coordination geometry leads to a highly selective catalyst complex. These AAC reactions represent a functional
Remote Stereoinduction in the Acylation of Fully Substituted Enolates: Tandem Reformatsky/Quaternary Claisen Condensations of Silyl Glyoxylates and β-Lactones
作者:Stephen N. Greszler、Justin T. Malinowski、Jeffrey S. Johnson
DOI:10.1021/ja108848d
日期:2010.12.15
glyoxylates and β-lactones to give highly functionalized Claisen condensation products. A heretofore undocumented instance of stereochemical 1,4-induction results in efficient transmission of β-lactonestereochemistry to the emerging fully substituted stereocenter. Second-stage transformations reveal that the five heteroatom-containing functionalities embedded within the products are entirely chemo-differentiated
Reformatsky 试剂依次与乙醛酸甲硅烷基酯和 β-内酯反应,得到高度官能化的克莱森缩合产物。迄今为止未记录的立体化学 1,4-诱导实例导致 β-内酯立体化学有效传输到新兴的完全取代的立体中心。第二阶段的转化表明,嵌入产品中的五个含杂原子的功能是完全化学分化的,这种情况允许快速组装 leustroducsin B 核心亚结构。
Mechanistic Investigations of the ZnCl<sub>2</sub>-Mediated Tandem Mukaiyama Aldol Lactonization: Evidence for Asynchronous, Concerted Transition States and Discovery of 2-Oxopyridyl Ketene Acetal Variants
作者:Cunxiang Zhao、T. Andrew Mitchell、Ravikrishna Vallakati、Lisa M. Pérez、Daniel Romo
DOI:10.1021/ja209163w
日期:2012.2.15
The ZnCl(2)-mediated tandem Mukaiyama aldol lactonization (TMAL) reaction of aldehydes and thiopyridyl ketene acetals provides a versatile, highlydiastereoselective approach to trans-1,2-disubstituted β-lactones. Mechanistic and theoretical studies described herein demonstrate that both the efficiency of this process and the high diastereoselectivity are highly dependent upon the type of ketene acetal
Studies of the tandem Mukaiyama aldol-lactonization (TMAL) reaction: A concise and highly diastereoselective route to β-lactones applied to the total synthesis of the potent pancreatic lipase inhibitor, (−)-Panclicin D
作者:Hong Woon Yang、Cunxiang Zhao、Daniel Romo
DOI:10.1016/s0040-4020(97)01029-6
日期:1997.12
A concise and highly diastereoselective route to β-lactones has been developed based on a tandemMukaiyamaaldol-lactonization employing thiopyridylsilylketene acetals and various aldehydes. (−)-Panclicin D, a potent pancreatic lipase inhibitor, was synthesized using this methodology. Recent optimization and extensions of this method are described which include variation of the silyl group and leaving