Deoxygenation of allylic alcohols to terminal olefins via stannylation/destannylation
作者:Yoshio Ueno、Hiroshi Sano、Makoto Okawara
DOI:10.1016/s0040-4039(00)77832-4
日期:1980.1
Deoxygenation of allylicalcohols to terminal olefins was performed via three steps; 1) [3,3]-sigmatropic rearrangement of O-allylxanthates, 2) the successive stannolysis with tributyltin hydride yielding allylic stannanes, and 3) final protolysis of allylic stannanes to terminal olefins.
Eu(OTf)<sub>3</sub>-Catalyzed Highly Regioselective Nucleophilic Ring Opening of 2,3-Epoxy Alcohols: An Efficient Entry to 3-Substituted 1,2-Diol Derivatives
In our study of the totalsynthesis of (+)-irciniastatin A, we found a need to develop a method that enables a C3-selective nucleophilicringopening of 2,3-epoxyalcohol by MeOH, by which we found that the use of combined catalytic amounts of Eu(OTf)3 and 2,6-di-tert-butyl-4-methylpyridine (DTBMP) enables the intended transformation to obtain 3-methoxy-1,2-diol efficiently. Promising features of a
Enantioselective Catalytic Crotylboration Based Syntheses of the C(7)–C(18(20)) Fragments of Polyketides Isolated from
<i>Streptomyces gramineus</i>
作者:Terézia Morávková、Eva Bednářová、Martin Kotora
DOI:10.1002/hlca.202100170
日期:2021.12
A general modular enantioselective synthetic approach to the C(7)–C(18) and the C(7)–C(20) fragment belonging to E-492, actinofuranone A, and JBIR-108 was developed. The crucial synthetic step relies on highlyenantioselective crotylboration of aldehydes catalyzed by a chiral TRIP PA giving rise to highly enantioenriched terminal alkenes (86 and 88 % ee on the preparative scale). The alkenes were subsequently
对属于 E-492、放线呋喃酮 A 和 JBIR-108 的 C(7)–C(18) 和 C(7)–C(20) 片段开发了一种通用的模块化对映选择性合成方法。关键的合成步骤依赖于由手性 TRIP PA 催化的醛的高度对映选择性巴豆基硼化,从而产生高度对映体富集的末端烯烃(制备规模为 86% 和 88% ee)。随后将烯烃转化为标题产物。其他重要的合成步骤包括 Ru 催化的烯烃交叉复分解和Suzuki偶联反应。该方法包括从容易获得的醛和其他反应伙伴开始的五个合成步骤。
COPPER (I)-CATALYZED REACTION OF ISOPRENE BROMOHYDRIN WITH ORGANOLITHIUM REAGENT
作者:Shuki Araki、Yasuo Butsugan
DOI:10.1246/cl.1980.185
日期:1980.2.5
The reaction of isoprene bromohydrin (1-bromo-2-methyl-3-buten-2-ol) (1) with ethyl-, propyl- and butyllithium in the presence of copper (I) iodide leads to the exclusive formation of the vinyl group migrated 2-alkyl-4-penten-2-ols (3d–3f), in contrast to the reaction with methyl-, phenyl- and benzyllithium, which yields the corresponding 2-methyl-4-substituted-2-buten-l-ols (2a–2c).
Regio- and Stereospecific Formation of Protected Allylic Alcohols via Zirconium-Mediated S<sub>N</sub>2‘ Substitution of Allylic Chlorides
作者:Richard J. Fox、Gojko Lalic、Robert G. Bergman
DOI:10.1021/ja075967i
日期:2007.11.1
regio- and stereospecific SN2‘ substitution reaction between a zirconium oxo complex and allylicchloride has been achieved. The resulting allylic alcohol or TBS-protected allylic ether products were isolated in good to excellent yields with a wide range of E-allylic chlorides. A mechanism for the SN2‘ allylic substitution consistent with kinetic, stereochemical, and secondary isotope effect studies