An environmentally benign and highly efficient supramolecular Michael addition of thiols from the secondary side of beta-cyclodextrin to alpha,beta-unsaturated compounds at the primary side in water is described in quantitative yields; products of undesirable side reactions resulting from polymerization are not observed; the use of cyclodextrin precludes the use of either acid or base and the catalyst
A simple and green procedure for the conjugate addition of thiols to conjugated alkenes employing polyethylene glycol (PEG) as an efficient recyclable medium
作者:Ahmed Kamal、D. Rajasekhar Reddy、Rajendar
DOI:10.1016/j.tetlet.2005.09.082
日期:2005.11
Polyethylene glycol (PEG) is found to be an inexpensive, nontoxic, environmentally friendly reaction medium for the conjugate addition of thiols to conjugated alkenes to afford the corresponding adducts in excellent yields under mild and neutral conditions. Products of undesirable side reactions resulting from polymerization are not observed. The use of PEG avoids the use of either acid or base catalysts for this conversion and moreover PEG can be recovered and reused. (c) 2005 Elsevier Ltd. All rights reserved.
Maleimide cycloadditions by sulfinyldienes: is the sulfur configuration the only controller of the diastereofacial selectivity?
作者:Maria C. Aversa、Anna Barattucci、Paola Bonaccorsi、Cristina Faggi、Eszter Gacs-Baitz、Assunta Marrocchi、Lucio Minuti、Aldo Taticchi
DOI:10.1016/j.tet.2005.05.089
日期:2005.8
Cyclohexylsulfinyl-3-methyl-1,3-butadienes 5, 6, and 1-[1-(cyclohexylsulfinyl)ethenyl]cyclohexene (7), easily prepared from cyclohexanethiol (1) via transient cyclohexanesulfenic acid (4), were reacted with N-phenylmaleimide under different conditions, at normal and high pressure. The stereochemical outcome of these cycloadditions contributes a better understanding of the relationships among different