One-pot synthesis of mixed ( )-1,2-bis(organylchalcogene)-1-alkenes precursors of the novel β-organylthio vinyllithium intermediates
摘要:
One-pot hydrochalcogenation of 1-phenylthioacetylenes using organylselenolate and organyltellurolate anions generated by the insertions of selenium and tellurium in n-organyl lithium produced (Z)-1,2-bis(organylchalcogene)-1-alkenes. The chemical reactivity of these mixed 1,2-bis(organylchalcogene)-1-alkenes was studied by Te/Li and Se/Li stereoretentive exchanges carried out with n-butyl lithium, furnishing the new intermediate species (Z)-beta-organylthio vinyllithium anions, which were trapped with aldehydes, to give the (Z)-3-hydroxy vinyl thioethers with total control of the regio- and stereochemistry. (c) 2010 Elsevier Ltd. All rights reserved.
Cu(i)-catalyzed aerobic cross-dehydrogenative coupling of terminal alkynes with thiols for the construction of alkynyl sulfides
作者:Yong Yang、Weibing Dong、Yisong Guo、Robert M. Rioux
DOI:10.1039/c3gc41330f
日期:——
and selective aerobiccross-dehydrogenativecoupling of terminalalkynes with thiols to construct alkynyl sulfides catalyzed by Cu(I) using molecular oxygen as the oxidant has been demonstrated under mild reaction conditions. The process is applicable to a wide range of alkynes and various thiols and is compatible with a variety of functional groups on both alkyne and thiol coupling partners.
Regioselectivity in the reaction of tantalum-unsymmetrical acetylene complexes with carbonyl compounds. Stereoselective preparation of 1-alkenyl sulfides, .alpha.,.beta.-unsaturated esters, and amides
Tantalum-alkyne complexes, derived by treatment of alkynes with low-valent tantalum (TaCl5 and zinc), react in situ with carbonyl compounds to give (E)-allylic alcohols stereoselectively. When unsymmetrical acetylenes are employed in the reaction, two regioisomeric allylic alcohols are produced. The regioselectivity of the reaction depends on the steric and electronic effects of the substituents on the acetylenes. For example, treatment of tantalum-alkyne complexes derived from methyl alkynyl sulfides with carbonyl compounds yields (E)-3-hydroxy-1-propenyl methyl sulfides in a regioselective manner. Tantalum-alkyne complexes derived from acetylenic esters react with carbonyl compounds regioselectively at the alpha-position of the esters to give Z-isomers of trisubstituted alpha,beta-unsaturated esters. In contrast, tantalum-alkyne complexes derived from acetylenic amides react with carbonyl compounds predominantly at the beta-position of the amides. The regioselectivity of the reaction between acetylenic amides and aldehydes, however, cannot be explained solely in terms of the steric and electronic effects of the substituents. Strong coordination of the amide group to the tantalum center could also be responsible for the observed selectivity, which is opposite to that observed with tantalum-acetylenic ester complexes.
Copper Nanoparticle Catalyzed Formation of C–S Bonds through Activation of S–S and C–H Bonds: An Easy Route to Alkynyl Sulfides
作者:Kang Park、Balaji Mohan、Sori Hwang、Hyunje Woo
DOI:10.1055/s-0035-1560458
日期:——
for copper nanoparticle catalyzed ligand-free S–Csp bond formation was developed by using dimethyl sulfoxide as the solvent, a base, and molecular oxygen as a green oxidant. This study provides a new catalytic route for the production of alkynyl sulfides through dual activation of S–S and C–H bonds. A wide range of alkynyl sulfides were synthesized on a large scale with a lowcatalystloading (0.5 mol%
One-pot synthesis of mixed ( )-1,2-bis(organylchalcogene)-1-alkenes precursors of the novel β-organylthio vinyllithium intermediates
作者:Miguel J. Dabdoub、Vânia B. Dabdoub、Marco A. Pereira、Adriano C.M. Baroni、Francisco A. Marques、Paulo R. de Oliveira、Palimécio G. Guerrero
DOI:10.1016/j.tetlet.2010.07.112
日期:2010.9
One-pot hydrochalcogenation of 1-phenylthioacetylenes using organylselenolate and organyltellurolate anions generated by the insertions of selenium and tellurium in n-organyl lithium produced (Z)-1,2-bis(organylchalcogene)-1-alkenes. The chemical reactivity of these mixed 1,2-bis(organylchalcogene)-1-alkenes was studied by Te/Li and Se/Li stereoretentive exchanges carried out with n-butyl lithium, furnishing the new intermediate species (Z)-beta-organylthio vinyllithium anions, which were trapped with aldehydes, to give the (Z)-3-hydroxy vinyl thioethers with total control of the regio- and stereochemistry. (c) 2010 Elsevier Ltd. All rights reserved.