A facile method for the synthesis of thiophene derivatives via the reaction of readily accessible dienol silyl ethers with elemental sulfur is described. Dienol silyl ethers and elemental sulfur, when heated at 180 °C in the presence of MS4A, provided 3-siloxythiophene derivatives in yields up to 98%. In this reaction, thiophene derivatives might be formed through 1,2-dithiines and eight-membered cyclic
Aryl-substituted thiophene 3-ols, derivatives and analogs, as lipoxygenase inhibitors
申请人:Merck & Co., Inc.
公开号:EP0318066A1
公开(公告)日:1989-05-31
Aryl substituted thiophenes 3-ols, its dihydro derivatives, 1-oxide and 1,1-dioxide analogs, as well as aryl substituted furans, are 5-lipoxygenase inhibitors useful in the treatment of inflammation and other leukotriene-mediated diseases.
1,4-Silatropy of <i>S</i>-α-Silylbenzyl Thioesters: A Convenient Route to Silyl Enol and Dienol Ethers Accompanied by C−C Bond Formation via Thiocarbonyl Ylides
A novel convenient method for the generation of thiocarbonyl ylides from readily accessible starting materials and the first synthetic application of in situ generated ylides in the synthesis of silyl enol and dienol ethers, accompanied by C-C bond formation, is described. Under completely neutral conditions without any catalyst or additive, thermal reactions of S-alpha-silylbenzyl thioesters in sealed tubes at 180 degreesC provided silyl enol and dienol ethers in good to excellent yields with high stereoselectivities. This procedure consists of a multistep reaction in a one-pot process, i.e., 1,4-silatropy of S-alpha-silylbenzyl thioesters to give thiocarbonyl ylides, 1,3-electrocyclization of the ylides to give thiiranes, and the extrusion of sulfur from thiiranes to give silyl enol and dienol ethers.
US4999436A
申请人:——
公开号:US4999436A
公开(公告)日:1991-03-12
Pd-Catalyzed, Ligand-Enabled Stereoselective 1,2-Iodine(III) Shift/1,1-Carboxyalkynylation of Alkynylbenziodoxoles
A PdII‐catalyzed 2:1 coupling reaction of alkynylbenziodoxole with carboxylic acid to afford (alk‐1‐en‐3‐ynyl)benziodoxole, which is efficiently promoted by an octahydrophenazine ligand, is reported. The reaction involves a Pd‐assisted 1,2‐iodine(III) shift of the alkynylbenziodoxole followed by stereoselective introduction of carboxy and alkynyl groups (the latter originating from another molecule