Asymmetric synthesis of spiro[chroman-3,3′-pyrazol] scaffolds with an all-carbon quaternary stereocenter via a oxa-Michael–Michael cascade strategy with bifunctional amine-thiourea organocatalysts

Content Provider	Semantic Scholar
Author	Zheng, Weiping Zhang, Jiayong Liu, Shuang Yu, Chengbin Miao, Zhiwei
Copyright Year	2015
Abstract	An efficient chiral bifunctional amine-thiourea catalysed cascade oxa-Michael–Michael addition of 4-alkenyl pyrazolin-3-ones to (E)-2-(2-nitrovinyl)phenol for the synthesis of chiral heterocyclic systems containing spiro[chroman-3,3′-pyrazol] scaffolds has been developed. This reaction afforded the desired products in high to excellent yields (up to 98%) with moderate to high enantioselectivities (up to 99%) and diastereoselectivities (up to 20:1) under low catalyst (15 mol%) concentration. This catalytic asymmetric reaction provides an efficient route toward the synthesis of chiral spiro[chroman-3,3′-pyrazol] derivatives containing three contiguous stereocenters which possess potential pharmaceutical activities.
Starting Page	91108
Ending Page	91113
Page Count	6
File Format	PDF HTM / HTML
DOI	10.1039/C5RA17792H
Volume Number	5
Alternate Webpage(s)	http://www.rsc.org/suppdata/c5/ra/c5ra17792h/c5ra17792h1.pdf
Alternate Webpage(s)	https://doi.org/10.1039/C5RA17792H
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article