Enantioselective Catalytic Conjugate Addition of Dialkylzinc Reagents using Copper–Phosphoramidite Complexes; Ligand Variation and Non-linear Effects
作者:Leggy A Arnold、Rosalinde Imbos、Alessandro Mandoli、André H.M de Vries、Robert Naasz、Ben L Feringa
DOI:10.1016/s0040-4020(00)00142-3
日期:2000.4
cyclohexenone and chalcone in order to assess the structural features that are important for stereocontrol. A sterically demanding amine moiety is essential to reach high e.e.’s. Enantioselectivities for chalcones up to 89% and for cyclic enones up to 98% were found. Studies on non-linear effects with the best ligands for both cyclohexenone and chalcone showed clear non-linear effects for both cyclic
Visible-Light-Mediated Oxidative Dimerization of Arylalkynes in the Open Air: Stereoselective Synthesis of (<i>Z</i>)-1,4-Enediones
作者:Donglei Wei、Fushun Liang
DOI:10.1021/acs.orglett.6b02926
日期:2016.11.18
An organic photoredox catalytic one-pot protocol is developed for the highly stereoselective synthesis of (Z)-1,4-enediones. The reaction starts directly from alkyne precursors, using 4-(4-cyanophenyl)-2,6-diphenylpyrylium tetrafluoroborate (CN-TPT) as an efficient photosensitizer and dioxygen in the air as a green oxidant. A Csp–Csp oxidative coupling/[4 + 2] cyclization (with dioxygen)/fragmentive
Synthesis of α-Stereogenic Amides and Ketones by Enantioselective Conjugate Addition of 1,4-Dicarbonyl But-2-enes
作者:Zhiyong Jiang、Yuanyong Yang、Yuanhang Pan、Yujun Zhao、Hongjun Liu、Choon-Hong Tan
DOI:10.1002/chem.200802601
日期:2009.5.4
Constructing α‐stereogenic amides and ketones: The highly regioselective and enantioselectiveconjugateaddition of 1,3‐dicarbonyl compounds to 1,4‐dicarbonyl but‐2‐enes has been developed with the chiral bicyclic guanidine as catalyst (ee values up to 97 %; see scheme).
Eine milde und einfache Synthese von Benzo[<i>c</i>]thiophenen und 4,7-Dihydrobenzo[<i>c</i>]thiophenen
作者:Wolfgang Volz、Jürgen Voß
DOI:10.1055/s-1990-26976
日期:——
A Mild and Simple Synthesis of Benzo[c]thiophenes and 4, 7-Di-hydrobenzo[c]thiophenes The synthesis of 1,3-disubstituted benzo[c]thiophenes and 4, 7-dihydrobenzo[c]thiophenes from o-diacylbenzenes and 4, 5-diacyl-cyclohexenes under very mild conditions is described.
Organocatalytic Asymmetric Conjugate Addition of 3-Monosubstituted Oxindoles to (<i>E</i>)-1,4-Diaryl-2-buten-1,4-diones: A Strategy for the Indirect Enantioselective Furanylation and Pyrrolylation of 3-Alkyloxindoles
3′‐disubstituted oxindoles—3‐furanyl‐ and 3‐pyrrolyl‐3‐alkyl‐oxindoles—in high yields and good enantioselectivities. Notably, the studies presented here sufficiently confirm that this two‐step strategy of sequential conjugate addition/Paal–Knorr cyclization is not only an attractive method for the indirect enantioselective heteroarylation of 3‐alkyloxindoles, but also opens up new avenues toward asymmetric synthesis