Samarium-based Grignard-type addition of organohalides to carbonyl compounds under catalysis of CuI
作者:Shuhuan Xiao、Chen Liu、Bin Song、Liang Wang、Yan Qi、Yongjun Liu
DOI:10.1039/d1cc00965f
日期:——
Grignard-type additions were readily achieved under the mediation of CuI (10 mol%) and samarium (2 equiv.) by employing various organohalides, e.g. benzyl, aryl, heterocyclic and aliphatic halides (Cl, Br or I), and diverse carbonylcompounds (e.g. carbonic esters, carboxylic esters, acid anhydrides, acyl chlorides, ketones, aldehydes, propylene epoxides and formamides) to afford alcohols, ketones
achieved by the use of samarium diiodide in catalytic amounts together with mischmetall (an alloy of the light lanthanides) as a coreductant. Plausible catalytic schemes are proposed. In addition, organocerium and -lanthanum reagents have been obtained from samarium diiodide catalysed reactions between organic halides and cerium or lanthanum metal, giving a newroute to organolanthanoid compounds. It also
An efficient one-pot route to synthesize tertiary alcohol compounds using Barbier–Grignard reaction of unactivated alkyl or arylbromides with ester in THF at 65 °C catalyzed by CuO has been developed and systematically investigated. A wide range of substituted tertiary alcohol compounds were obtained in good to high yields. The reaction is highly chemoselective. The mechanism involving the leaving
Synthesis, Structural Characterization, and Reactivity of Zirconium Complexes Containing Trimethylenemethane-Based Ligands
作者:George Rodriguez、Guillermo C. Bazan
DOI:10.1021/ja962545s
日期:1997.1.1
General synthetic routes to zirconium metallocene-like complexescontaining derivatives of the dianionic trimethylenemethane (TMM) ligand are presented. One approach consists of reacting the dilithium salts of TMM, tribenzylidenemethane (TBM), tert-butyltribenzylidenemethane (t-Bu-TBM), and dibenzylidenemethylenemethane (DBM) with either Cp*ZrCl3 or CpZrCl3(DME). In the case of the small TMM fragment
combination of “TiCl2(cat)” and Zn (cat=catecholate) facilitates the homolytic cleavage of “non-activated” alcohol C−O bonds. All aliphatic primary, secondary and tertiary alcohols serve as good substrates. This method was applied to radical conjugate addition reactions successfully, and mechanistic studies indicate that alkyl chlorides are not intermediates. The active species is a 1 : 2 complex of alkoxide