Herein, an efficient route to enantioenriched organosilanes, containing two consecutive stereogenic centers, from enals and β‐silyl enones under carbene organocatalysis is described. Under mild reaction conditions, this transition‐metal‐free strategy exhibits a broad substrate scope, and excellent diastereo‐ and enantioselectivity.
Stereoselective Construction of 1,3-Disilylcyclopentane Derivatives by Scandium-Catalyzed [3+2] Cycloaddition of Allylsilanes to β-Silylenones
作者:Kazuhiro Okamoto、Eisuke Tamura、Kouichi Ohe
DOI:10.1002/anie.201404218
日期:2014.9.15
The Sc(OTf)3‐catalyzed [3+2] cycloaddition of allylsilanes to β‐silyl‐α,β‐unsaturated ketones (β‐silylenones) has been developed to form five‐membered syn‐1,3‐disilylketones diastereoselectively through the rearrangement of the silicon substituents on the allylsilane. Stabilization of the carbocation intermediates by a double silicon effect plays a key role in directing the course of the reaction to
Carbene-Catalyzed Enantioselective Synthesis of γ-Keto-β-silyl Esters and Amides
作者:Yuxia Zhang、Xuan Huang、Jingcheng Guo、Chenlong Wei、Minghua Gong、Zhenqian Fu
DOI:10.1021/acs.orglett.0c03589
日期:2020.12.18
A variety of γ-keto-β-silyl esters and amides, most with extremely high enantioselectivities, were efficiently prepared via a carbene-catalyzed formal [4 + 2] annulation followed by ring opening with nucleophiles. The resulting compounds from this one-pot strategy can be easily converted into enantioenriched β,σ-dihydroxyl esters.
Reaction of the title compound (2) with lead thiocyanate gave phenylthio(trimethylsilyl)methyl isothiocyanate (3a) which further reacted with aromatic aldehydes in the presence of fluoride ion to afford oxazoles in good yields. Compound (2) also reacted with silyl enol ethers to give β-silyl ketones which were capable of being converted into β-functionalized vinylsilanes.
Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions
作者:Akhil K Dubey、Raghunath Chowdhury
DOI:10.3762/bjoc.17.177
日期:——
carbonyl compounds catalyzed by bifunctional squaramide catalysts has been developed. This methodology offers both enantiomers of β-silyl nitroalkanes in good to excellent yields (up to 92%) and enantioselectivities (up to 97.5% ee) under solvent-free conditions at room temperature. Control experiments reveal that the presence of a β-silyl group in the enones is crucial for high reactivityunder the optimized