Iodine-catalyzed Michael addition of mercaptans to α,β-unsaturated ketones under solvent-free conditions
作者:Cheng-Ming Chu、Shijay Gao、M.N.V. Sastry、Ching-Fa Yao
DOI:10.1016/j.tetlet.2005.05.099
日期:2005.7
A simple and efficient method for the Michael reaction between various mercaptans and α,β-unsaturated ketones using a catalytic amount of iodine (5 mol %) to generate the 1,4-adduct has been reported. The significant features of the iodine catalyzed Michael addition are (a) operational simplicity, (b) inexpensive reagents, (c) high yields of products, (d) the use of relatively low or nontoxic reagents
The Intramolecular Participation of Sulfide Linkage on the Reactivity of Carbenes and Diazoalkanes. II. Alkylcarbenes and Diazoalkanes Bearing Arylthio and Allylthio Groups on β-Carbon
作者:Kiyosi Kondo、Iwao Ojima
DOI:10.1246/bcsj.48.1490
日期:1975.5
β-Arylthio- and β-allylthioalkylcarbenes were generated from the corresponding ketones by a modification of the Bamford-Stevens method. Chemical evidence for the formation of novel cyclic ylides, i.e., thietanonium ylides, by an intramolecular electrophilic addition of the carbene to the sulfur atom was obtained. The resulting ylides underwent various types of rearrangements to afford cyclopropyl sulfides, thiaazulenes, thietanes, and/or tetrahydrothiophenes. The mechanisms and the relative amounts of the transition energies for these rearrangements are discussed. An intramolecular cycloaddition of β-allyl- and β-crotylthioalkyldiazoalkanes is also described. The final products of the reaction were 3-thiabicyclo[4.1.0]heptanes. A thiabicyclic pyrazoline, which is presumed to be an intermediate of the cycloaddition, could be isolated in the case of the thermal decomposition of 4-allylthio-4-methylpentan-2-one tosylhydrazone.
The iron(III) chloride-mediated 1,4-addition of mercaptans to α,β-unsaturated ketones and esters under solvent free conditions
作者:Cheng-Ming Chu、Wan-Ju Huang、Chaowei Lu、Pohsi Wu、Ju-Tsung Liu、Ching-Fa Yao
DOI:10.1016/j.tetlet.2006.07.151
日期:2006.10
The 1,4-addition of various thiols to alpha,beta-unsaturated ketones was completed rapidly in the presence of a catalytic amount (2-3 mol %) of anhydrous iron(III) chloride under solvent free conditions and an air atmosphere. Anhydrous iron(III) chloride is more active than that of other ferric salts. With more reactive and/or less steric reagents (1a-c and/or 2a-2c), expeditious conditions (short reaction times at room temperature) could be employed. With less reactive and/or steric reagents (1d-g and/or 2d-e), a slight increase in reaction time was required, but high yields were obtained. The FeCl3 catalyst causes preferential interactions with alpha,beta-unsaturated ketones present in the reaction. (c) 2006 Published by Elsevier Ltd.
Ceric ammonium nitrate (CAN) as a green and highly efficient promoter for the 1,4-addition of thiols and benzeneselenol to α,β-unsaturated ketones
作者:Cheng-Ming Chu、Shijay Gao、M.N.V. Sastry、Chun-Wei Kuo、Chaowei Lu、Ju-Tsung Liu、Ching-Fa Yao
DOI:10.1016/j.tet.2006.12.018
日期:2007.2
efficient process for the 1,4-addition of thiols and benzeneselenols to various α,β-unsaturatedketones using a catalytic amount of CAN with excellent product yields is described. This inexpensive, nontoxic, and readily available catalytic ceric(IV) ammonium nitrate system efficiently catalyzes conjugate addition reactions between thiol derivatives and various α,β-unsaturatedketones under solvent-free conditions