Visible-Light-Mediated Ru-Catalyzed Synthesis of 3-(Arylsulfonyl)but-3-enals via Coupling of α-Allenols with Diazonium Salts and Sulfur Dioxide
作者:Fernando Herrera、Amparo Luna、Pedro Almendros
DOI:10.1021/acs.orglett.0c03482
日期:2020.12.18
arenediazonium salts is presented. The three-component reaction which is promoted by visible light can be easily accomplished using DABSO as a sulfur dioxide surrogate in the presence of a photoredox catalyst. In this manner, a broad range of electron-rich and electron-deficient aryl substituents are well accommodated in the sulfonylation–rearrangement cascade to afford the 2,2-disubstituted 3-(arylsulfonyl)but-3-enals
Palladium-catalyzed carbocyclization–cross-coupling reactions of two different allenic moieties: synthesis of 3-(buta-1,3-dienyl) carbazoles and mechanistic insights
作者:Benito Alcaide、Pedro Almendros、José M. Alonso、Israel Fernández
DOI:10.1039/c2cc32015k
日期:——
A palladium-catalyzed chemo-, regio- and stereoselective carbocyclizationâcross-coupling sequence of two different α-allenols to afford 3-(E-buta-1,3-dienyl) carbazoles is reported.
The synergy between metal catalysis and radical chemistry allows to surpass previous limitations of the reactions between allenols and sulfonylating reagents. Considering that previous studies of the reactivity of the allenol moiety with sulfonylating reagents have been limited to addition and rearrangement reactions lacking cyclization, we decided to modify the protocol for achieving a catalytic
Regioselectivity Switch Based on the Stoichiometry: Stereoselective Synthesis of Trisubstituted Vinyl Epoxides by Cu‐Catalyzed 3‐
<i>exo</i>
‐
<i>trig</i>
Cyclization of α‐Allenols
作者:Pablo Esteban、Fernando Herrera、Daniel San Martín、Amparo Luna、Pedro Almendros
DOI:10.1002/adsc.202200592
日期:2022.9.20
terminal allene carbon via a 5-endo path and forms dihydrofurans. A copper-catalyzed protocol brought about a reversed regioselectivity, generating a series of trisubstituted epoxides through a 3-exo-cyclization/sulfonylation cascade. The current stoichiometry control of regioselectivity may open singular opportunities in chemical transformations.
Au(I) as a π-Lewis Base Catalyst: Controlled Synthesis of Sterically Congested Bis(triflyl)enals from α-Allenols
作者:Mireia Toledano-Pinedo、Teresa Martínez del Campo、Hikaru Yanai、Pedro Almendros
DOI:10.1021/acscatal.2c03858
日期:2022.10.7
A gold-catalyzed bis[(trifluoromethyl)sulfonyl]ethylation of α-allenols, which allows the preparation of sterically congested bis(triflyl)enals bearing quaternary carbon centers, is presented. This sequence differs from the conventional reaction pathway of α-allenols under π-acid catalysis, because in our case Au(I) functions as a π-Lewis base catalyst rather than a π-Lewis acid to activate the allene