Organocatalyzed [3 + 2] Annulation of Cyclopropenones and β-Ketoesters: An Approach to Substituted Butenolides with a Quaternary Center
作者:Xuanyi Li、Chunhua Han、Hequan Yao、Aijun Lin
DOI:10.1021/acs.orglett.6b03737
日期:2017.2.17
An unprecedented organocatalyzed [3 + 2] annulation of cyclopropenones and β-ketoesters has been developed. This reaction provides a direct approach to highly substitutedbutenolides with a quaternary center in moderate to good yields. The preliminary mechanism study verified that the enol intermediate is crucial to the reaction outcome and the intermolecular esterification and intramolecular Michael
Fully Substituted Conjugate Benzofuran Core: Multiyne Cascade Coupling and Oxidation of Cyclopropenone
作者:Liangliang Yao、Qiong Hu、Li Bao、Wenjing Zhu、Yimin Hu
DOI:10.1021/acs.orglett.1c01304
日期:2021.7.2
multiyne cascade coupling has been developed. This chemistry provides a novel, simple, and efficient approach to synthesize fullysubstituted conjugate benzofuran derivatives from simple substrates under mild conditions. The density functional theory (DFT) calculations reveal that the unique homolytic cleavages of cyclopropenone and molecular oxygen are crucial to the success of this reaction.
I<sub>2</sub>-DMSO Mediated Multicomponent [3+2] Annulation Reaction: An Approach to Pyrrolo[2,1-<i>a</i>]isoquinoline Derivatives with a Quaternary Center
An I2-DMSO mediated multicomponent [3+2] cascade annulation reaction using methyl ketones, 1,2,3,4-tetrahydroisoquinolines (THIQ) and cyclopropenones as readily available substrates has been developed. This metal-free process involves N–H/α-C(sp3)–H trifunctionalization of THIQ and C–C bond cleavage of cyclopropenone, providing a direct approach to obtain pyrrolo[2,1-a]isoquinoline derivatives with
Phosphine-Catalyzed Ring-Opening Regioselective Addition of Cyclopropenones with Amides
作者:Huamin Wang、Yibo Wei、Yongjun He、Tian-Juan He、Ying-Wu Lin
DOI:10.1021/acs.joc.4c00941
日期:2024.7.19
A series of amides, including α-bromo hydroxamates, N-alkoxyamides, and N-aryloxyamides, were subjected to phosphine-catalyzed ring-opening O-selective addition with cyclopropenones, producing various special α,β-unsaturated esters containing oxime ether motif, in moderate to excellent yields, with high regioselectivity, and exclusive O-selectivity. The methodology is highly atom-economical, with simple