نتایج جستجو برای: wittig reaction

تعداد نتایج: 412686  

Journal: :Chemical science 2016
Feng Gao Byeong-Seon Kim Patrick J Walsh

Control of chemoselectivity is one of the most challenging problems facing chemists and is particularly important in the synthesis of bioactive compounds and medications. Herein, the first highly chemoselective tandem C(sp3)-H arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers is presented. The efficient and operationally simple protocols enable generation of either arylation products...

Journal: :Angewandte Chemie 2009
Christopher J O'Brien Jennifer L Tellez Zachary S Nixon Lauren J Kang Andra L Carter Stephen R Kunkel Katherine C Przeworski Gregory A Chass

The imine intermediate generated by the addition of primary amine to the cinnamaldehyde is trapped by the N-isocyaniminotriphenylphosphorane (Ph3PNNC) and a carboxylic acid, and leads to the formation of the corresponding iminophosphorane intermediate. The 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediate. The reactions were comp...

2002
Vassilios Loukas Theodoros Markidis

A method for the synthesis of long chain diamines and tetramines starting from natural α-amino acids is reported. Diamines and tetramines were prepared through the Wittig olefination reaction of N-protected amino aldehydes obtained from phenylalanine and lysine. A 1,2,17,18-tetramine was synthesized using (2S)-1-azido-2-[bis(tertbutoxycarbonyl)-amino]-5-oxopentane as key-intermediate compound.

Journal: :Organic & biomolecular chemistry 2014
Pathi Suman Bhimapaka China Raju

A facile carbohydrate-based highly stereoselective synthetic route has been developed for the cytospolide P (1) from D-ribose for the first time. Key steps of the synthesis include Wittig homologation, regioselective epoxide ring opening, Sharpless asymmetric epoxidation, Evans aldol reaction, and Yamaguchi macrolactonization.

2011
Robert E. Maleczka Feng Geng

Since its discovery the rearrangement of R-metalated ethers, particularly the [2,3]-Wittig rearrangement, has been the subject of intensive mechanistic and synthetic investigations.1 Relative to the [2,3]-shift, the [1,2]-Wittig rearrangement has received relatively little publicity. Most studies of the [1,2]-Wittig have been mechanistic in origin, resulting in the widely accepted theory that t...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید