Gleason-type chiralauxiliaries were used for the synthesis of a novel class of sulfonium salts, obtained via methylation of the sulfide with Meerwein's salt. The salts were reacted with aldehydes under basic conditions to provide epoxy amides, which were reduced to their corresponding epoxy alcohols in excellent enantiomeric excesses. Interestingly, it was feasible to synthesize both enantiomeric
Organocatalytic asymmetric epoxidation reactions in water–alcohol solutions
作者:Wei Zhuang、Mauro Marigo、Karl Anker Jørgensen
DOI:10.1039/b512542a
日期:——
enantioselective organocatalytic epoxidation of alpha,beta-unsaturated aldehydes in aqueous solutions is presented. By the screening of the reaction conditions for the epoxidation of cinnamic aldehyde applying hydrogen peroxide as the oxidant and 2-[bis-(3,5-bis-trifluoromethyl-phenyl)-trimethylsilanyloxy-methyl]-pyrrolidine as the catalyst, a highly stereoselective reaction has been developed. The scope
The Development of Cyclic Sulfolanes as Novel and High-Affinity P2 Ligands for HIV-1 Protease Inhibitors
作者:Arun K. Ghosh、Hee Yoon Lee、Wayne J. Thompson、Chris Culberson、M. Katharine Holloway、Sean P. McKee、Peter M. Munson、Tien T. Duong、Anthony M. Smith
DOI:10.1021/jm00034a016
日期:1994.4
synthesis of a novel series of proteaseinhibitors incorporating conformationally constrained cyclicligands for the S2-substrate binding site of HIV-1protease is described. We recently reported urethanes of 3-tetrahydrofuranyl as P2ligands for HIV-1proteaseinhibitors. Subsequently, we have found that the urethane of 3(S)-hydroxysulfolane further increased the in vitro potency of these inhibitors. Furthermore
Asymmetric Induction in Methyl Ketone Aldol Additions to α-Alkoxy and α,β-Bisalkoxy Aldehydes: A Model for Acyclic Stereocontrol
作者:David A. Evans、Victor J. Cee、Sarah J. Siska
DOI:10.1021/ja061010o
日期:2006.7.1
systematic study of methyl ketone aldol additions under nonchelating conditions with α-alkoxy and α,β-bisalkoxy aldehydes is described. Additions to aldehydes containing a single α-alkoxy stereocenter generally provide the product diastereomers in accord with the Cornforth/polar Felkin-Anh models for carbonyl addition. Vicinal asymmetric induction is sensitive to the aldehyde α-alkyl substituent, but is relatively
Enantioselective organocatalytic epoxidation using hypervalent iodine reagents
作者:Sandra Lee、David W.C. MacMillan
DOI:10.1016/j.tet.2006.07.055
日期:2006.12
A rare example of a hypervalentiodine reagent participating in a 1,4-heteroconjugate addition reaction is reported for the organocatalytic, asymmetric epoxidation of α,β-unsaturated aldehydes using imidazolidinone catalyst 1. Development of an ‘internal syringe pump’ effect via the slow release of iodosobenzene from an iminoiodinane source provides high levels of reaction efficiency and enantiomeric
据报道,使用咪唑烷酮催化剂1可以使α,β-不饱和醛发生有机催化,不对称环氧化,这是参与1,4-杂合物加成反应的高价碘试剂的一个罕见例子。通过从亚碘碘烷源缓慢释放碘代苯来开发“内部注射泵”效应,可在缺电子烯烃的不对称环氧化中提供高水平的反应效率和对映体控制。进行了15 N NMR研究,以阐明在原型氧化剂存在下导致催化剂耗竭的反应途径。这些NMR研究也为亚氨基碘烷作为内部缓释氧化剂的应用提供了机理基础,以规避这些催化剂的消耗途径。