Combining Asymmetric Catalysis with Natural Product Functionalization through Enantioselective α-Fluorination
摘要:
An examination into the derivatization of various natural products using newly developed alpha-fluorination methodology is disclosed. An activated ketene enolate, generated from in acid chloride, is allowed to react with an electrophilic fluorine source (NFSi). Quenching the reaction with a nucleophilic natural product produces biologically relevant alpha-fluorinated carbonyl derivatives of select chemotherapeutics, antibiotics, and other pharmaceuticals.
Method of synthesizing optically enriched alpha-halo-esters, and product and composition therefrom
申请人:——
公开号:US20030050501A1
公开(公告)日:2003-03-13
A method of synthesizing highly optically enriched &agr;-halo-esters comprises reacting acid halides with a cinchona alkaloid catalyst and a base to form intermediate ketenes. The ketenes are reacted with electrophilic halogenating reagents to produce &agr;-halo-esters with high enantiomeric excess. The base can be an inorganic salt. The thus-formed &agr;-halo-esters have utility in synthesizing other optically-pure materials.
The Development of the First Catalyzed Reaction of Ketenes and Imines: Catalytic, Asymmetric Synthesis of β-Lactams
作者:Andrew E. Taggi、Ahmed M. Hafez、Harald Wack、Brandon Young、Dana Ferraris、Thomas Lectka
DOI:10.1021/ja0258226
日期:2002.6.1
resulting from the development of a catalyzed reaction of ketenes (or their derived zwitterionic enolates) and imines. The products of these asymmetric reactions can serve as precursors to a number of enzyme inhibitors and drug candidates as well as valuable synthetic intermediates. We present a detailed study of the mechanism of the beta-lactam forming reaction with proton sponge as the stoichiometric
Tropolonate Salts as Acyl-Transfer Catalysts under Thermal and Photochemical Conditions: Reaction Scope and Mechanistic Insights
作者:Demelza J. M. Lyons、Claire Empel、Domenic P. Pace、An H. Dinh、Binh Khanh Mai、Rene M. Koenigs、Thanh Vinh Nguyen
DOI:10.1021/acscatal.0c03702
日期:2020.11.6
strong nucleophilicity and photochemical activity, can promote the coupling reaction between alcohols and carboxylic acid anhydrides or chlorides to give products under thermal or blue light photochemical conditions. Kinetic studies and density functional theory calculations suggest interesting mechanistic insights for reactions promoted by this acyl-transfer catalytic system.
From Bifunctional to Trifunctional (Tricomponent Nucleophile–Transition Metal–Lewis Acid) Catalysis: The Catalytic, Enantioselective α-Fluorination of Acid Chlorides
作者:Jeremy Erb、Daniel H. Paull、Travis Dudding、Lee Belding、Thomas Lectka
DOI:10.1021/ja2014345
日期:2011.5.18
fluorination of a ketene enolate intermediate. We discovered, for the first time, that a third catalyst, a Lewis acidic lithium salt, could be introduced into a dually activated system to amplify yields of aliphatic products, primarily through activation of the fluorinatingagent. Through our mechanistic studies (based on kinetic data, isotopic labeling, spectroscopic measurements, and theoretical calculations)