Development of a Highly α-Regioselective Metal-Mediated Allylation Reaction in Aqueous Media: New Mechanistic Proposal for the Origin of α-Homoallylic Alcohols
This paper described a general method to obtain α-adduct homoallylic alcohols using indium, zinc, and tin in water. A new mechanism was proposed to account for the formation of these synthetically difficult-to-obtain molecules. Generally, this method can be performed with a wide range of aldehydes and allylic halides with just 6 equiv of water added, giving the α-adduct in high selectivities. To account
Gallium-mediated allyl transfer from bulky homoallyl alcohol to aldehydes or alkynes: Control of dynamic σ-allylgalliums based on retro-allylation reaction
reagent and gallium trichloride, bulky homoallylalcohols undergo gallium-mediated retro-allylation reaction to provide σ-allylgallium reagents. The σ-allylgallium reagents generated were applied to carbonyl allylation. The retro-allylation reaction generates (Z)- and (E)-σ-crotylgalliums stereospecifically, starting from erythro- and threo-homoallyl alcohols, respectively. The stereochemically defined
α-Regioselective carbonyl allylation by an allylic tin compound prepared from 1-bromobut-2-ene and tin(<scp>II</scp>) bromide at a nonpolar organic–aqueous interface
1-Bromobut-2-ene on a dichloromethane–water biphasic system at 25 °C causes α-regioselective addition to aldehydes with SnBr2 to produce 1-substituted pent-3-en-1-ols, and causes γ-regioselective addition to aldehydes with SnBr2–Bu4NBr to produce 1-substituted 2-methylbut-3-en-1-ols.
The stereochemical course of the allylation and propargylation of several aldehydes with crotyl and propargyl halides using zinc powder as the condensing agent in cosolvent/water(salt) media have been extensively studied. Radical ions of well-defined geometry such as [CH(2)=CHCH(CH(3))Br](*)(-) are thought to be formed through an electron-transfer process, which seems to be accelerated by the high
Stereochemical and spectroscopic studies on the reaction of allylstannanes with aldehydes
作者:Scott E. Denmark、Eric J. Weber、Thomas M. Wilson、Timothy M. Willson
DOI:10.1016/0040-4020(89)80016-x
日期:1989.1
for the reacting double bonds in the Lewis acid-induced reaction of allylic stannanes and aldehydes has been examined. Model system 1 shows a strong and Lewis-acid independent preference for the synclinal orientation of double bonds. A possible stereoelectronic basis for this preference is discussed. A13C-NMR spcctroscopic study of the reaction between crotyltrialkylstannanes (9) and acetaldehyde (10)