نتایج جستجو برای: propargylic alcohols
تعداد نتایج: 11787 فیلتر نتایج به سال:
Carbonyl rhenium(I) complexes are efficient catalysts for the regioselective isomerization of terminal propargylic alcohols into α,β-unsaturated aldehydes or ketones which can be used as an unprecedented recyclable catalytic system (up to 10 consecutive runs) in the ionic liquid [BMIM][PF(6)].
An easily available BINOL-Ti(O(i)Pr)4 catalyst system is found to activate the reaction of Zn powder with EtI for the asymmetric alkyne addition to aldehydes at room temperature. It allows the synthesis of a number of synthetically useful chiral propargylic alcohols with both high yields and high enantioselectivity (up to >96% ee).
The activity of HBF4 (aqueous solution) as a catalyst in propargylation reactions is presented. Diverse types of nucleophiles were employed in order to form new C-O, C-N and C-C bonds in technical acetone and in air. Good to excellent yields and good chemoselectivities were obtained using low acid loading (typically 1 mol-%) under simple reaction conditions.
The enantioselective addition of phenylethynylzinc to aldehydes catalyzed by a series of cyclopropane-based amino alcohol ligands 7 was investigated. The reactions afforded chiral propargylic alcohols in high yields (up to 96%) and with excellent enantioselectivities (up to 98% ee) under mild conditions. Furthermore, studies on the structural relationship show that the matching of the chiral ce...
Reactions of propargylic alcohols with CO(2) in a [BMIm][PhSO(3)]/CuCl catalytic system to produce the corresponding alpha-methylene cyclic carbonates were conducted with high yields. Mild reaction conditions, enhanced rates, improved yields, and recyclable ionic liquid catalyst systems are the remarkable features exhibited in this process. Furthermore, the use of large amounts of tertiary amin...
An efficient and practical copper-catalyzed highly regio- and stereoselective borylcupration of internal alkynes with bis(pinacolato)diboron using a catalytic amount of K(2)CO(3) as base producing Z-alkenylboron compounds has been demonstrated by applying the ligand effect: commercially available electron-rich tris(p-methoxyphenyl) phosphine ensures a smooth and efficient reaction. Functionaliz...
The ability of the hydrosoluble ruthenium(II) complexes [RuCl2(h-arene)(PTA)] 3a–d, [RuCl2(h-arene)(PTA-Bn)] 4a–d, [RuCl2(h-arene)(DAPTA)] 5a–d, [RuCl2(h-arene)(TPPMS)] 6a–d (arene = C6H6, p-cymene, 1,3,5-C6H3Me3, C6Me6) to promote the atom-economic formation of b-oxo esters, by addition of carboxylic acids to terminal propargylic alcohols in water has been explored. Scope, limitations and cata...
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