Enantioselective Synthesis of Highly Substituted Chromans via the Oxa-Michael–Michael Cascade Reaction with a Bifunctional Organocatalyst
作者:Prasenjit Saha、Arnab Biswas、Nagaraju Molleti、Vinod K. Singh
DOI:10.1021/acs.joc.5b01751
日期:2015.11.6
A highly enantioselective synthesis of chiral chroman derivatives via an oxa-Michael–Michael cascade reaction has been developed using a bifunctionalthioureaorganocatalyst. The products were obtained with excellent enantioselectivities (up to >99%), good yields (up to 95%), and diastereoselectivities (up to 5:1).
Synthesis of methylene cyclopropane-fused chromenes and dihydroquinolines by sequential [4 + 2]- and [1 + 2]-annulation
作者:Tianyu Lu、Xuange Zhang、Zhiwei Miao
DOI:10.1039/d0ob00389a
日期:——
A base promoted sequential [4 + 2]- and [1 + 2]-annulation of 2-hydroxychalcones or 2-tosylaminochalcones with prop-2-ynylsulfonium salts has been developed to give the corresponding methylene cyclopropane fused dihydroquinolines or chromenes in moderate to good yields. This transformation has advantage of wide substrate scope and functional group tolerance as well as excellent regioselectivity. Prop-2-ynylsulfonium
Enantioselective Synthesis of Chromanones via a Peptidic Phosphane Catalyzed Rauhut–Currier Reaction
作者:Robert J. H. Scanes、Oleg Grossmann、André Grossmann、David R. Spring
DOI:10.1021/acs.orglett.5b00971
日期:2015.5.15
The enantioselective intramolecular Rauhut-Currier reaction has been developed using a bifunctional dipeptidic phosphane catalyst, providing a direct access to biologically active alpha-methylene-delta-valerolactones in high yields and enantiomeric excesses. The novel catalyst is accessible in only four steps, from commercial sources and exhibits unusual binding selectivities for a small molecule, suggesting the possibility for long-range interactions between the catalyst and the substrate.
Gupta, A. K.; Singh, V. K.; Pant, Umesh C., Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1983, vol. 22, # 10, p. 1057 - 1059
作者:Gupta, A. K.、Singh, V. K.、Pant, Umesh C.
DOI:——
日期:——
GUPTA, A. K.;SINGH, V. K.;PANT, UMESH, C., INDIAN J. CHEM., 1983, 22, N 10, 1057-1059