The Experts below are selected from a list of 52683 Experts worldwide ranked by ideXlab platform
David Guijarro - One of the best experts on this subject based on the ideXlab platform.
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arene catalysed reductive desulfonylation and desulfinylation reactions new routes for alkyllithiums
Tetrahedron, 1995Co-Authors: Emma Alonso, David GuijarroAbstract:Abstract The reaction of alkyl phenyl sulfones ( 1 ) with an excess of lithium powder and a catalytic amount of naphthalene (8 mol %) in the presence of a Carbonyl Compound or chlorotrimethylsilane (Barbier-type conditions) in THF at temperatures ranging between −78 and 20°C leads, after hydrolysis, to the expected products ( 2 ) arising from the corresponding alkyllithium generated in situ . When the same methodology is applied to sulfolene ( 3 ) or different alkyl phenyl sulfoxides ( 6 ), cyclic sulfinates 5 or products 2 are, respectively, obtained, the yields being, in general modest.
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naphthalene catalysed reductive desulfonylation with lithium alkyllithiums from alkyl phenyl sulfones
Tetrahedron Letters, 1994Co-Authors: David GuijarroAbstract:Abstract The reaction of alkyl aryl sulfones 1 with an excess of lithium powder and a catalytic amount of naphthalene (8 mol %) in the presence of a Carbonyl Compound [PriCHO, PhCHO, Et2CO, ( CH 2)5CO] or trimethylchlorosilane (Barbier-type conditions) in THF at temperatures ranging between −78 and 20°C leads, after hydrolysis with water, to the expected coupling products, arising from the corresponding alkyllithium in situ generated, in 30–61% yields.
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organolithium reagents by reductive decyanation of nitriles with lithium and a catalytic amount of 4 4 di tert butyl biphenyl in a barbier type reaction
Tetrahedron, 1994Co-Authors: David GuijarroAbstract:Abstract The reaction of different nitriles 1 with an excess of lithium powder (1:14 molar ratio) and a catalytic amount of 4,4′-di-tert-butylbiphenyl (5 mol %) in the presence of a Carbonyl Compound (Barbier-type conditions) in THF at low temperature (−30 or −78°C) leads to the corresponding Compounds 2 resulting from the coupling between the electrophile and the organolithium intermediate arising from a reductive decyanation of the starting nitrile 1. This new reaction can be also applied to the use of trimethylchlorosilane as electrophile at 0°C.
Graham Pattison - One of the best experts on this subject based on the ideXlab platform.
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transition metal free homologative cross coupling of aldehydes and ketones with geminal bis boron Compounds
Organic Letters, 2017Co-Authors: Thomas C Stephens, Graham PattisonAbstract:We report a transition-metal-free coupling of aldehydes and ketones with geminal bis(boron) building blocks which provides the coupled, homologated Carbonyl Compound upon oxidation. This reaction not only extends an alkyl chain containing a Carbonyl group, it also simultaneously introduces a new Carbonyl substituent. We demonstrate that enantiopure aldehydes with an enolizable stereogenic center undergo this reaction with complete retention of stereochemistry.
Asit K Chakraborti - One of the best experts on this subject based on the ideXlab platform.
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catalyst free conjugated addition of thiols to α β unsaturated Carbonyl Compounds in water
Organic Letters, 2006Co-Authors: Gopal L Khatik, Raj Kumar, Asit K ChakrabortiAbstract:Catalyst-free conjugate addition of thiols to α,β-unsaturated Carbonyl Compounds in water is reported. β-Sulfido Carbonyl Compounds were formed at room temperature, in short times and with excellent chemoselectivity. Competitive dithiane/dithiolane formation, transesterification, and ester cleavage were not observed. Water played a dual role in simultaneously activating the α,β-unsaturated Carbonyl Compound and the thiol. This new methodology constitutes an easy, highly efficient, and green synthesis of β-sulfido Carbonyl Compounds.
Xiaodi Yang - One of the best experts on this subject based on the ideXlab platform.
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silver triflate catalyzed three component reaction of 2 alkynylbenzaldehyde sulfonohydrazide and α β unsaturated Carbonyl Compound
Chemical Communications, 2010Co-Authors: Xiaodi YangAbstract:A highly efficient silver triflate-catalyzed three-component reaction of 2-alkynylbenzaldehyde, sulfonohydrazide, and α,β-unsaturated Carbonyl Compound is reported, which affords H-pyrazolo[5,1-a]isoquinoline-1-carboxylates in good yield.
Alakananda Hajra - One of the best experts on this subject based on the ideXlab platform.
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a simple and green procedure for the synthesis of α aminophosphonate by a one pot three component condensation of Carbonyl Compound amine and diethyl phosphite without solvent and catalyst
Green Chemistry, 2002Co-Authors: Brindaban C Ranu, Alakananda HajraAbstract:A simple, general, efficient and greener method has been developed for the synthesis of α-aminophosphonates through a solvent-free and catalyst-free one-pot three-component condensation of Carbonyl Compound, amine and diethyl phosphite.