نتایج جستجو برای: alkenes
تعداد نتایج: 5720 فیلتر نتایج به سال:
BACKGROUND Cytochrome P450 OleTJE from Jeotgalicoccus sp. ATCC 8456, a new member of the CYP152 peroxygenase family, was recently found to catalyze the unusual decarboxylation of long-chain fatty acids to form α-alkenes using H2O2 as the sole electron and oxygen donor. Because aliphatic α-alkenes are important chemicals that can be used as biofuels to replace fossil fuels, or for making lubrica...
2-(3-Benzyloxy)prop-1-ynyl)benzaldehyde with PtCl(2) in toluene would form Pt-pyryliums that underwent [3+2] cycloaddition with alkenes to the oxygen-bridged (5H-benzo[7]annulen-5-ylidene)platinum(ii) intermediates with good stereoselectivities. Their tandem rearrangement afforded diverse types of polycycles depending on the electronic nature of the alkenes.
A system for transfer hydrogenation of alkenes, composed of a ruthenium metathesis catalyst and HCOOH, is presented. This operationally simple system can be formed directly after a metathesis reaction to effect hydrogenation of the metathesis product in a single-pot. These hydrogenation conditions are applicable to a wide range of alkenes and offer remarkable selectivity.
An improved syntheses of substituted benzhydryl derivatives has been developed. This facile two-step procedure involves C-C bond formation from O-diphenylmethyltrichloroacetimidate and C-nucleophiles in the presence of TMSOTf. The C-nucleophiles include arenes, alkenes, alkene silylated C-nucleophiles and trimethylsiloxy alkenes to give a series substituted benzhydryl derivatives in excellent y...
A variety of terminal alkynes are facilely convertible into cis-boryl(stannyl)alkenes with inverse regioselectivity to those of the previous borylstannylation by the copper-catalyzed three-component reaction using a masked diboron. The synthetic utility of the resulting boryl(stannyl)alkenes has been demonstrated by chemoselective coupling reactions.
Copper-catalyzed functionalization of terminal or 1,1-disubstituted alkenes with bis(pinacolato)diboron and methanol provides formal hydroboration products with exceptional regiocontrol favoring the branched isomer. Pairing this procedure with photocatalytic cross-couplings using iridium and nickel cocatalysis provides an effective, highly regioselective procedure for the hydroarylation of term...
Herein, we report a Pd-catalysed alkoxycarbonylation of alkenes based on the use of a recyclable CO2 reduction product, the crystalline and air-stable N-formylsaccharin, as a CO surrogate. The carbonylation proceeds under ambient conditions in an exceptionally complementary regioselective fashion yielding the desired branched products from styrene derivatives and valuable linear esters from alk...
Phosphorodiselenoic acid esters with a binaphthyl group were reacted with alkenes in the presence of Bu3SnH and AIBN to give phosphonoselenoic acid esters in moderate to good yields. The addition of a phosphoroselenoyl group to alkenes proceeded in an anti-Markovnikov fashion. The diastereoselectivity was improved by the introduction of substituents to 3,3'-positions of a binaphthyl group.
Nickel-catalyzed intermolecular allylic substitution of simple alkenes (ethylene and alpha olefins) is described. This method is the first catalytic intermolecular process for direct allylation of nonconjugated, nonstrained simple alkenes. Catalyst loadings as low as 2.5 mol % Ni afford the desired product in high yield in both gram-scale and smaller scale coupling reactions.
We report the first enantioselective Rh-catalyzed Markovnikov hydroboration of unactivated terminal alkenes. Using a novel sp2-sp3 hybridized diboron reagent and water as a proton source, a broad range of alkenes undergo hydroboration to provide secondary boronic esters with high regio- and enantiocontrol.
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