Facile synthesis and desulfurization of 5-(phenylthio)pyrano[3,2-c][1]benzopyrans starting from 5-phenylthio-4-penten-1-ols and salicylaldehyde via in situ intramolecular cycloaddition of substituted o-quinonemethides
摘要:
5-(Phenylthio)pyrano[3,2-c][1]benzopyrans (6) were successfully synthesized in high yield by the reaction of 5-phenylthio-4-penten-1-ol (5) and salicylardehyde (1) in benzene in the presence of p-toluenesulfonic acid and trimethyl orthoformate. trans,trans-Isomer 6a and cis,cis-isomer 6d were produced as major products from (E)-5 and (Z)-5, respectively. Treatment of 6a with lithium 4,4'-di-tert-butylbiphenyl or Raney Ni (W-4) lead to trans-pyrano[3,2-c][1]benzopyran 4b which is very difficult to make by direct cycloaddition using unsubstituted 4-penten-1-ol (2b). (C) 2000 Elsevier Science Ltd. All rights reserved.
Highly stereoselective anti-Markovnikov hydrothiolation of alkynes and electron-deficient alkenes by a supported Cu-NHC complex
作者:Yong Yang、Robert M. Rioux
DOI:10.1039/c4gc00642a
日期:——
A robust silica-supported Cu-NHC complex catalyzed highly stereoselective anti-Markovnikov hydrothiolation of alkynes or electron-deficient alkenes to construct C–S bonds.
Evolution of a Polyene Cyclization Cascade for the Total Synthesis of (−)-Cyclosmenospongine
作者:Klaus Speck、Thomas Magauer
DOI:10.1002/chem.201605029
日期:2017.1.23
We report a full account on the development of a unique cationic polyenecyclization for the total synthesis of the tetracyclic meroterpenoid (−)‐cyclosmenospongine. A highly convergent three‐component coupling strategy enabled rapid access to individual cyclization precursors that were tested for their reactivity. The successful transformation generates three rings and sets four consecutive stereocenters
Air Oxidative Radical Oxysulfurization of Alkynes Leading to α-Thioaldehydes
作者:Shao-Fang Zhou、Xiang-Qiang Pan、Zhi-Hao Zhou、Adedamola Shoberu、Pei-Zhi Zhang、Jian-Ping Zou
DOI:10.1021/acs.joc.5b00641
日期:2015.5.15
Air oxidative radical oxysulfurization of alkynes initiated by 0.5 mol % tert-butyl hydroperoxide with arylthiols is described. The reaction proceeded at room temperature in the presence of 5% mol water to afford selective a-thioaldehydes.