Squaric acid as an impressive organocatalyst for Michael addition in water
作者:Najmadin Azizi、Elham Saki、Mahtab Edrisi
DOI:10.1016/j.crci.2011.07.003
日期:2011.11
Résumé A simple, green, and environmentally benign protocol for squaric acid (5 mg) catalyst conjugate addition of aromatic amines and thiols to unsaturated carbonyl compounds in water in good to excellent yields is developed. The advantages of low sensitivity toward moisture and oxygen, high tolerance of different functional groups, green reaction media and efficient recyclability make this organocatalyst suitable for both laboratory and industrial scale synthesis of β-substituted carbonyls under very mild conditions.
We disclose a direct C(sp)–, C(sp2)–, and C(sp3)–H thiolation reaction using β-sulfinylesters as the versatile sulfur source. The key step of this protocol is chemoselective C–S bond cleavage of the sulfoniumsalts that are formed in situ from the corresponding alkenes, alkynes, and 1,3-dicarboxyl compounds with β-sulfinylesters. The successful capture of the acrylate byproduct supports a retro-Michael
Direct biocatalysed synthesis of first sulfur-, selenium- and tellurium- containing <scp>l</scp>-ascorbyl hybrid derivatives with radical trapping and GPx-like properties
作者:Damiano Tanini、Beatrice Lupori、Gianni Malevolti、Moira Ambrosi、Pierandrea Lo Nostro、Antonella Capperucci
DOI:10.1039/c9cc02427a
日期:——
6-O-l-Ascorbyl selenoesters, thioesters and telluroesters can be efficiently and directly prepared from l-ascorbic acid and suitable functionalised chalcogenoesters through lipase-catalysed transesterification reactions.
Sulfone derivatives, process for their production and use thereof
申请人:——
公开号:US20030187023A1
公开(公告)日:2003-10-02
A compound represented by the formula:
1
wherein R is a cyclic hydrocarbon group, or the like; W is a bond, or the like; X is a divalent hydrocarbon group, or the like; Y and Z are each independently —N(R
6
)— or the like; ring A is a nitrogen-containing heterocyclic ring, or the like; R5 and R6 are independently hydrogen atom, a hydrocarbon group, or the like; Z′ is imidoyl group, or the like; a is 0, 1 or 2; and b is 0 or 1, or a salt thereof.
作者:Christopher B. W. Phippen、James K. Beattie、Christopher S. P. McErlean
DOI:10.1039/c0cc02502j
日期:——
The conjugate addition of anilines onto unsaturated ketones, esters and N-acylpyrroles was investigated. Based on a recently proposed explanation for the phenomenon of on-water catalysis, operationally simple and mild reaction conditions for effecting these addition reactions have been developed. The success of these additions provides further support for the acid-catalysed nature of on-water chemistry.