Geminal Dicarboxylates as Carbonyl Surrogates for Asymmetric Synthesis. Part II. Scope and Applications
作者:Barry M. Trost、Chul Bom Lee
DOI:10.1021/ja003775g
日期:2001.4.1
An enantioselectivesynthesis of allylic esters has been achieved by a novel asymmetricalkylation of allylic gem-dicarboxylates. The catalyst derived from palladium(0) and R,R-1,2-di(2'-diphenylphosphinobenzamido)cyclohexene efficiently induced the alkylation process with a variety of nucleophiles to provide allylic esters as products in good yield. High regio- and enantioselectivities were observed
烯丙基酯的对映选择性合成已通过烯丙基双羧酸酯的新型不对称烷基化实现。源自钯 (0) 和 R,R-1,2-二(2'-二苯基膦基苯甲酰胺基) 环己烯的催化剂有效地诱导了各种亲核试剂的烷基化过程,以良好的产率提供烯丙酯作为产物。在与大多数衍生自丙二酸的亲核试剂的烷基化中观察到高区域选择性和对映选择性,而在与反应性较低的亲核试剂(如双(苯磺酰基)乙烷)的反应中获得中等水平的 ee。在后一种情况下,缓慢的添加程序被证明是有效的,导致 ee 的显着改善。烷基化产物的效用通过几种合成有用的转化(包括烯丙基异构化、烯丙基烷基化和克莱森重排。使用这些反应,初始烯丙基碳-氧键的手性可以以高立体化学保真度的可预测方式转移到新的碳-氧、碳-碳或碳-氮键上。通过取代反应将宝石二酯转化为手性酯相当于通过稳定的亲核试剂进行不对称羰基加成。与随后发生的具有高立体特异性的反应相结合,烯丙基双羧酸盐作为双烯丙基转化的合成子。
Asymmetric hydroformylation and hydrocarboxylation of enamides. Synthesis of alanine and proline
作者:Y. Becker、A. Eisenstadt、J. K. Stille
DOI:10.1021/jo01299a022
日期:1980.5
Catalytic Asymmetric Protonation of α-Amino Acid-Derived Ketene Disilyl Acetals Using <i>P</i>-Spiro Diaminodioxaphosphonium Barfates as Chiral Proton
作者:Daisuke Uraguchi、Natsuko Kinoshita、Takashi Ooi
DOI:10.1021/ja105945z
日期:2010.9.8
Chiral diaminodioxaphosphonium salts have been developed and their unique abilities as a chiral proton have been revealed through the establishment of a highly enantioselective protonation of alpha-amino acid-derived ketene disilyl acetals.
The Goldilocks Principle in Phase Labeling. Minimalist and Orthogonal Phase Tagging for Chromatography-Free Mitsunobu Reaction
作者:Mariann Szigeti、Zoltán Dobi、Tibor Soós
DOI:10.1021/acs.joc.8b00014
日期:2018.3.2
An inexpensive and chromatography-free Mitsunobu methodology has been developed using low molecular weight and orthogonally phase-tagged reagents, a tert-butyl-tagged highly apolar phosphine, and a water-soluble DIAD analogue. The byproduct of the Mitsunobureactions can be removed by sequential liquid–liquidextractions using traditional solvents such as hexanes, MeOH, water, and EtOAc. Owing to the