在可能的金氧化还原催化下,炔烃的立体选择性硫代烯丙基化反应效率高(催化剂负载量低至0.1%,产率高达99%),底物范围广(各种炔烃,分子间和分子内方式)。金(I)催化剂既充当炔烃活化的π-酸,又充当Au I / III偶联的氧化还原催化剂,而原位生成的sulf阳离子则起弱氧化剂的作用。这种新颖的方法为金的氧化还原催化提供了令人兴奋的系统,而无需强氧化剂。
Chemoselective Rearrangement Reactions of Sulfur Ylide Derived from Diazoquinones and Allyl/Propargyl Sulfides
作者:Sijia Yan、Junxin Rao、Cong-Ying Zhou
DOI:10.1021/acs.orglett.0c03493
日期:2020.11.20
three types of rearrangement reactions of sulfur ylidederivedfrom diazoquinones and allyl/propargyl sulfides. With Rh2(esp)2 as the catalyst, diazoquinones react with allyl/propargyl sulfides to form a sulfur ylide, which undergoes a chemoselective tautomerization/[2,3]-sigmatropic rearrangement reaction, a Doyle–Kirmse rearrangement/Cope rearrangement cascade reaction, or a Doyle–Kirmse rearrangement/elimination
Silica-promoted facile synthesis of thioesters and thioethers: a highly efficient, reusable and environmentally safe solid support
作者:Basudeb Basu、Susmita Paul、Ashis K. Nanda
DOI:10.1039/b925620b
日期:——
An efficient, mild and rapid procedure for the acylation and alkylation of aromatic and aliphatic thiols mediated on a silica gel surface at room temperature is described. The protocol allows the protection of thiols under neutral heterogeneous conditions without requiring any bases or Lewis acids, and the silica gel used as the promoter can be recycled for several runs without any loss of activity.
Hemin Catalyzed Dealkylative Intercepted [2, 3]‐Sigmatropic Rearrangement Reactions of Sulfonium Ylides with 2, 2, 2‐Trifluorodiazoethane
作者:Xiaojing Yan、Chang Li、Xiaofei Xu、Xiaoyong Zhao、Yuanjiang Pan
DOI:10.1002/adsc.201901534
日期:2020.5.12
A dealkylative intercepted [2, 3]‐sigmatropic rearrangement reaction of allylic sulfides with 2, 2, 2‐trifluorodiazoethane (CF3CHN2) is reported, the commercially available and biocompatible catalyst hemin was found to efficiently catalyze this transformation across a diverse set of allylic sulfides with in situ generated CF3CHN2, providing excellent yields (up to 99%) under mild condition without
Yb(<scp>iii</scp>)-catalysed <i>syn</i>-thioallylation of ynamides
作者:Manash Protim Gogoi、Rajeshwer Vanjari、B. Prabagar、Shengwen Yang、Shubham Dutta、Rajendra K. Mallick、Vincent Gandon、Akhila K. Sahoo
DOI:10.1039/d1cc02611a
日期:——
incorporating a sulfide moiety at the α-position and an allyl group at the β-position of the ynamide. The transformation is successful under ytterbium(III)-catalysis, providing access to highly substituted thioamino-skipped-dienes with broad substrate scope. Thus, tetrasubstituted olefins (with four different functionalgroups: amide, phenyl, thioaryl/alkyl, and allyl on the carbon centers) are made in a single
本文报道的是一种顺式结合在α位的烯丙基在炔酰胺的β位的硫化物部分和ynamides的-thioallylation。该转化在镱 ( III ) 催化下成功,提供了获得具有广泛底物范围的高度取代的硫氨基跳过二烯的途径。因此,四取代的烯烃(在碳中心上具有四个不同的官能团:酰胺、苯基、硫代芳基/烷基和烯丙基)是由易于获得的 ynamides 一步制成的,从而保持完整的原子经济性。该反应可扩展到由炔酰胺合成selenoamino二烯的顺式-selenoallylation。DFT 研究和控制实验提供了对反应机制的深入了解。
Difluoroacetaldehyde
<i>N</i>
‐Triftosylhydrazone (DFHZ‐Tfs) as a Bench‐Stable Crystalline Diazo Surrogate for Diazoacetaldehyde and Difluorodiazoethane
study, we developed a bench-stable difluoroacetaldehyde N-triftosylhydrazone (DFHZ-Tfs) as an operationally safe diazo surrogate that can release in situ two low-molecular-weight diazoalkanes, diazoacetaldehyde (CHOCHN2 ) or difluorodiazoethane (CF2 HCHN2 ), in a controlled fashion under specific conditions. DFHZ-Tfs has been successfully employed in the Fe-catalyzed cyclopropanation and Doyle-Kirmse