71094-28-5Relevant articles and documents
An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes
Khairnar, Pankaj V.,Lung, Tsai-Hui,Lin, Yi-Jung,Wu, Chi-Yi,Koppolu, Srinivasa Rao,Edukondalu, Athukuri,Karanam, Praneeth,Lin, Wenwei
supporting information, p. 4219 - 4223 (2019/06/17)
α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further, proper functionalization of α-haloketoximes and a change of conditions allowed the chemoselective synthesis of chromenone-oximes as well as rearranged isoxazoles, thereby realizing a diversity-oriented synthesis.
Aerobic Oxidative Cycloaddition of α-Chlorotosylhydrazones with Arylamines: General Chemoselective Construction of 1,4-Disubstituted and 1,5-Disubstituted 1,2,3-Triazoles under Metal-Free and Azide-Free Conditions
Bai, Hui-Wen,Cai, Zhong-Jian,Wang, Shun-Yi,Ji, Shun-Jun
supporting information, p. 2898 - 2901 (2015/06/30)
A novel synthetic approach toward 1,4-disubstituted 1,2,3-triazoles and 1,5-disubstituted 1,2,3-triazoles by aerobic oxidative cycloaddition of α-chlorotosylhydrazone with primary aryl amine has been developed. Significantly, the reaction proceeds smoothl
Copper(I)-catalyzed addition of grignard reagents to in situ-derived N -sulfonyl azoalkenes: An umpolung alkylation procedure applicable to the formation of up to three contiguous quaternary centers
Hatcher, John M.,Coltart, Don M.
supporting information; experimental part, p. 4546 - 4547 (2010/06/13)
The α-alkylation of N-sulfonyl hydrazones via in situ-derived azoalkenes provides an umpolung approach to ketone α-alkylation that has considerable potential with regard to catalysis and the direct incorporation of functionality not amenable to the use of enolate chemistry. Herein, we describe the first Cu(I)-catalyzed addition of Grignard reagents to in situ-derived N-sulfonyl azoalkenes. This method is remarkable in its ability to deliver highly sterically hindered compounds that would be difficult or impossible to synthesize via traditional enolate chemistry, including those having up to three contiguous quaternary centers.
