Transition-Metal-Free Allylic Borylation of 1,3-Dienes
作者:Ricardo J. Maza、Elliot Davenport、Núria Miralles、Jorge J. Carbó、Elena Fernández
DOI:10.1021/acs.orglett.9b00531
日期:2019.4.5
This work explains the reactivity of diboron reagents with 1,3-dienes in a transition-metal-free context. The sole addition of Na2CO3 (30 mol %) to bis(pinacolato)diboron in MeOH allows the 1,4-hydroboration of cyclic and noncyclic 1,3-dienes. The electronic influence on the substrate guarantees the conjugated 1,4-hydroboration versus 1,2-diboration. DFT calculations show that the distribution of charge
这项工作解释了在无过渡金属的情况下乙硼试剂与1,3-二烯的反应性。将Na 2 CO 3(30mol%)仅添加至在MeOH中的双(频哪醇)二硼中,可以使环状和非环状的1,3-二烯进行1,4-氢硼化。电子对底物的影响保证了共轭的1,4-氢硼化与1,2-二硼化。DFT计算表明,烯丙基阴离子中间体中的电荷分布决定着1,4-氢硼化的选择性,而二烯试剂中有利的反式构型决定了对烯丙基硼酸E酯的偏爱。
Desymmetrization and Kinetic Resolution of Endoperoxides Using a Bifunctional Organocatalyst
作者:Sarah V. A.-M. Legendre、Christopher J. Sumby、Amir Karton、Ben W. Greatrex
DOI:10.1021/acs.joc.3c00278
日期:2023.8.18
Bifunctional thiourea/amine organocatalysts have been used for the desymmetrization of meso-endoperoxides using the Kornblum–DeLaMare reaction, giving 4-hydroxyketones in 78–98% yields with ≤98:2 enantioselectivity. The influence of the catalyst structure, solvent, and temperature was examined. The most promising catalyst was applied to the kinetic resolution of racemic endoperoxides to give enantioenriched
Palladium-Catalyzed Enantioselective Hydrohydrazonation of 1,3-Dienes
作者:Shaozi Sun、Qinglong Zhang、Weiwei Zi
DOI:10.1021/acs.orglett.3c02729
日期:2023.12.1
We presented a method for synthesizing allylic chiral hydrazones from 1,4-disubstituted 1,3-dienes and hydrazones through a (R)-DTBM-Segphos-Pd(0)-catalyzed hydrohydrazonation reaction. This transformation has a wide range of substrates and good functional group tolerance. The desired products were obtained in medium to high yield and good regio- and enantioselectivity. Synthetic transformation of
我们提出了一种通过 ( R )-DTBM-Segphos-Pd(0) 催化的氢腙反应从 1,4-二取代 1,3-二烯和腙合成烯丙基手性腙的方法。该转化具有广泛的底物范围和良好的官能团耐受性。以中等至高产率和良好的区域选择性和对映选择性获得了所需产物。证明了产物合成转化为各种含氮手性化合物。
Ganushchak,N.I. et al., Journal of Organic Chemistry USSR (English Translation), 1969, vol. 5, p. 111 - 113