Gold‐Catalyzed [3+2]‐Annulations of α‐Aryl Diazoketones with the Tetrasubstituted Alkenes of Cyclopentadienes: High Stereoselectivity and Enantioselectivity
作者:Ching‐Nung Chen、Wei‐Min Cheng、Jian‐Kai Wang、Tzu‐Hsuan Chao、Mu‐Jeng Cheng、Rai‐Shung Liu
DOI:10.1002/anie.202012611
日期:2021.2.23
This work reports gold‐catalyzed [3+2]‐annulations of α‐diazo ketones with highly substituted cyclopentadienes, affording bicyclic 2,3‐dihydrofurans with high regio‐ and stereoselectivity. The reactions highlights the first success of tetrasubstituted alkenes to undergo [3+2]‐annulations with α‐diazo carbonyls. The enantioselective annulations are also achieved with high enantioselectivity using chiral
Development of a [2 + 2]-Nitroso/Alkene Cycloaddition Using Sodium Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate Catalyst: Controlled Chemoselectivity of Two Equilibrating Isomeric Intermediates
作者:Jia-Xuan Chen、Prakash D. Jadhav、Ching-Nung Chen、Rai-Shung Liu
DOI:10.1021/acs.orglett.1c01987
日期:2021.8.20
Sodium tetrakis[3,5-bis(trifluoromethyl)-phenyl]borate (NaBArF) catalyzes the [2 + 2] cycloaddition of 1,4-disubstituted cyclopenta-1,3-dien-2-yl esters with nitrsobenzene in toluene, affording two isolable regioisomers of 6-oxa-7-azabicyclo[3.2.0] heptanes, which thermally rearrange into the same 4-aminocyclopent-1-en-3-ones. In the case of 4-substituted cyclopenta-1,3-dien-2-yl esters, their initial
type of structure units is full of challenge due to their congested chemical environment. Herein, we report a new gold(I) self-relay catalysis merging [3,3]-sigmatropic rearrangement/Nazarov cyclization with allylic alkylation starting from 1,3-enyne acetates and allylic alcohols, producing a wide range of synthetically important allyl cyclopentenones with an all-carbon quaternary stereocenter in good
An efficient and regioselective protocol for the construction of 5‐bromo/iodo cyclopentenones from gold(I)‐catalyzed tandem cycloisomerization/electrophilic halogenation of 1,3‐enyne esters with NXS in a one‐pot two‐step operation has been developed. The synthetic utility was further demonstrated by the scale‐up preparation of one example followed by its conversion to the corresponding α‐substituted
Gold-Catalyzed Rearrangement of α-Carbonyl Cyclopropanes to Form 3-(Cyclopenta-1,3-dien-1-ylmethyl)oxindoles via a Postulated 1,5-Enolate Shift
作者:Amit Vijay Sasane、Tung-Chun Kuo、Mu-Jeng Cheng、Rai-Shung Liu
DOI:10.1021/acs.orglett.2c02117
日期:2022.7.22
Gold-catalyzed stereoselectivesynthesis of spirocyclopropyloxindolesfrom diazooxindoles and 1,2,4-substituted dienes is described. The aim of this work is to report a novel rearrangement of these spirocyclopropyloxindoles with a gold catalyst to yield 3-(cyclopenta-1,3-dien-1-ylmethyl)oxindoles. Our experimental data exclude a reversible process in the gold-catalyzed cyclopropanation. With DFT