Addition reactions of organic carbanion equivalents via hydrazones in water
作者:Yi-Zhan Wang、Qi Liu、Liang Cheng、Song-Chen Yu、Li Liu、Chao-Jun Li
DOI:10.1016/j.tet.2020.131889
日期:2021.1
The addition of organometallic reagents to unsaturated bonds is one of the most powerful tools for carbon–carbon bondformations. Alkylation throughorganometallic reagents requires stoichiometric quantity of metal and tedious anhydrous operation in most cases. Here, we report “umpolung” nucleophilic additions of hydrazones to Michael acceptors, carbonyls and imines in water. Under the catalysis of
Allyliodide reacts in situ with cerium amalgam to generate allyl cerium iodide, which in turn reacts with ketones to yield homoallylic alcohols in good yields.
Conjugate addition of benzyl copper reagents to α,α-enoates and -enones.
作者:Pieter S. Van Heerden、Barend C.B. Bezuidenhoudt、Jacobus A. Steenkamp、Daneel Ferreira
DOI:10.1016/s0040-4039(00)74218-3
日期:1992.4
Several benzylic copper reagents, BnCu(CN)MgCl, Bn2CuMgCl, BnCu-TMSCl-HMPA, and BnCu-TMSCl-TMEDA, facilitate the conjugateaddition of the benzyl ligand to α,β-enones, but only BnCu-TMSCl-TMEDA gave high yields with α,β-unsaturated esters.
Free radical-promoted conjugate addition of activated bromo compounds using titanocene(III) chloride as the radical initiator
作者:Samir Kumar Mandal、Samaraesh Jana、Subhas Chandra Roy
DOI:10.1016/j.tetlet.2005.07.007
日期:2005.9
Free radical-promoted conjugate addition of activated bromo compounds to α,β-unsaturated ketones and reactive α,β-unsaturated esters has been described using titanocene(III) chloride (Cp2TiCl) as the radical initiator. Cp2TiCl was prepared in situ from commercially available Cp2TiCl2 and activated zinc dust in THF.
Palladium-catalysed arylation of tert-cyclobutanols with arylbromide involving enantioselective C-Cbondcleavage affords chiral ketones with moderate to good enantioselectivity.