Mukaiyama–Michael addition of a ketenesilylacetal on a cyclic α,β-unsaturated ketone, followed by the addition of a glyoxylic, aromatic or heteroaromatic imine. According to the nature of the silyl group the adducts resulting from this tandem process are isolated as ketones or as enoxysilanes. The presence of a coordinating group on the imine increases the rate of the reaction.
Chain propagation determines the chemo- and regioselectivity of alkyl radical additions to C–O <i>vs.</i> C–C double bonds
作者:Tiffany O. Paulisch、Felix Strieth-Kalthoff、Christian Henkel、Lena Pitzer、Dirk M. Guldi、Frank Glorius
DOI:10.1039/c9sc04846d
日期:——
Investigations into the selectivity of intermolecular alkyl radical additions to C–O- vs. C–C-double bonds in α,β-unsaturated carbonyl compounds are described. Therefore, a photoredox-initiatedradical chain reaction is explored, where the activation of the carbonyl-group through an in situ generated Lewis acid – originating from the substrate – enables the formation of either C–O or the C–C-addition
Tandem Mukaiyama Michael–aldol reactions catalysed by samarium diiodide
作者:Nicolas Giuseppone、Jacqueline Collin
DOI:10.1016/s0040-4020(01)00902-4
日期:2001.10
Samarium diiodide is an efficient precatalyst for tandemMichael–aldolreactions, which allow the formation of two carbon–carbon bonds by successive additions of a ketene silyl acetal and an aldehyde on cyclic α,β-unsaturated ketones. The adducts are isolated as silyl ethers, in good yields, and in some cases with high diastereoselectivities when the reactions are performed at low temperatures. Comparative
Mukaiyama aldol and Michael reactions catalyzed by lanthanide iodides
作者:Nicolas Giuseppone、Pierre Van de Weghe、Mohamed Mellah、Jacqueline Collin
DOI:10.1016/s0040-4020(98)00791-1
日期:1998.10
Samariumdiiodide is an efficient catalyst precursor which allows the formation of condensation products between various carbonylcompounds and ketene silyl acetals or enoxysilanes. With α,β-unsaturated carbonylcompounds, 1,2- or 1,4-additions are observed according to the structure of the substrate. α,β-Unsaturated ketones yield to enoxysilanes by selective Michael additions. Aldol poducts are isolated
Catalytic Michaelreaction between trimethylsilyl enolates and α,β-unsaturated carbonylcompounds by using a Lewis base such as lithium benzamide or lithium succimide in a DMF solvent proceeded smoothly to afford the corresponding Michael adducts.