β-Functionalization of Carboxylic Anhydrides with β-Alkyl Substituents through Carbene Organocatalysis
作者:Zhichao Jin、Shaojin Chen、Yuhuang Wang、Pengcheng Zheng、Song Yang、Yonggui Robin Chi
DOI:10.1002/anie.201408604
日期:2014.12.1
The first NHC‐catalyzed functionalization of carboxylicanhydrides is described. In this reaction, the β carbon behaves as a nucleophilic carbon and undergoes asymmetric reactions with electrophiles. Anhydrides with challenging β‐alkyl substituents work effectively.
The catalytic asymmetricepoxidation of 2‐arylidene‐1,3‐diketones using aqueous 30% H2O2 as oxidant has been successfully realized by a N,N′‐dioxide–scandium(III) triflate [Sc(OTf)3] complex, giving the corresponding products in moderate to good yields (up to 85%) with excellent enantioselectivities (up to 99% ee) under mild reaction conditions without extra additives.
N,N'-二氧化物-三氟甲磺酸scan [Sc(OTf)3 ]配合物已成功实现了使用30%H 2 O 2水溶液作为氧化剂催化2-亚芳基-1,3-二酮的催化不对称环氧化。,在温和的反应条件下,无需额外的添加剂,即可以中等至良好的收率(高达85%)提供具有良好对映选择性(高达99%ee)的相应产品。
Preparation of Tetrasubstituted Furans via Intramolecular Wittig Reactions with Phosphorus Ylides as Intermediates
作者:Tzu-Ting Kao、Siang-en Syu、Yi-Wun Jhang、Wenwei Lin
DOI:10.1021/ol101080q
日期:2010.7.2
functional furans can be efficiently generated in one step at room temperature within 10 min to 21 h in moderate to high yields (60−99%). The reaction was proposed to proceed via intramolecular Wittig-type reactions, using phosphorus ylides as intermediates.
The Reactions of α-Ylidene (Vinylidene, Benzylidene, Styrylmethylidene) Bis[carbonyls] with Copper Mono/Bis[carbonylcarbenoids]
作者:Gökçe Merey、Mustafa Kaya、Olcay Anaç
DOI:10.1002/hlca.201200004
日期:2012.8
bis‐ketones/bis‐esters/bis‐keto esters with dimethyl diazomalonate and ethyl diazoacetate were studied. Total steric/electronic convenience of the present reaction paths was investigated. Methoxy/nitro substituents in m‐/p‐positions on benzylidene biscarbonyls did not alter the general routes of the reactions, supporting concerted mechanism. Dihydrobenzoxepine/oxepine formation was sterically sensitive
Synthesis of Functionalized Furans via Chemoselective Reduction/Wittig Reaction Using Catalytic Triethylamine and Phosphine
作者:Chia-Jui Lee、Tzu-Hsiu Chang、Jhen-Kuei Yu、Ganapuram Madhusudhan Reddy、Ming-Yu Hsiao、Wenwei Lin
DOI:10.1021/acs.orglett.6b01781
日期:2016.8.5
An efficient protocol for the synthesis of highly functionalized furans via intramolecular Wittigreaction has been developed using catalytic amounts of phosphine and triethylamine. Silyl chloride served as the initial promoter to activate the phosphine oxide. Reduction of the activated phosphine oxide by hydrosilane resulted in generation of phosphine, while decomposition of Et3N·HCl resulted in regeneration