to be among the most valuable reagents in modern organic synthesis, providing a rapid access to a wide array of transformations, including the construction of C–C and C-heteroatom bonds, their use as dienophile-reactive groups has been rare. Herein we report the Diels–Alder (DA) reaction of (unsymmetrical) gem-diborylalkenes. These reactions provide a general and efficient method for the stereoselective
尽管偕二硼基烯烃被认为是现代有机合成中最有价值的试剂之一,可以快速进行各种转化,包括构建 C-C 和 C-杂原子键,但它们作为亲双烯反应基团的用途已经已经很少见了。在此,我们报道了(不对称)宝石二硼基烯烃的狄尔斯-阿尔德(DA)反应。这些反应为偕二硼基烯烃的立体选择性转化以快速获得1,1-双硼基环己烯提供了一种通用且有效的方法。使用与硼化二烯和偕二硼基烯烃相同的 DA 反应歧管,我们还开发了 1,1,2-三-和 1,1,3,4-四(硼酸盐)环己烯家族的简洁、高度区域选择性合成方法。目前缺乏有效合成途径的化合物。此外,DFT 计算可以深入了解控制这些 DA 反应的化学选择性、区域选择性和立体选择性的潜在因素。该方法还提供了偕二硼基降冰片烯的立体发散合成。开环复分解聚合(ROMP)证明了偕二硼基降冰片烯结构单元的实用性,为首次合成偕二硼基聚合物提供了高度模块化的方法。此外,这些聚合物已成功
Diels–Alder Reaction of 2,3-Bis(pinacolatoboryl)-1,3-butadiene: Facile Preparation of 1,2-Bis(pinacolatoboryl)cyclohexenes and -1,4-cyclohexadiene
Diels–Alder reaction of 2,3-bis(pinacolato)boryl-1,3-butadiene with electron-deficient alkenes and dimethyl acetylenedicarboxylate proceeded smoothly upon heating, giving rise to the corresponding ...
One, two, three, four: A copper(I)–phosphine complex catalyzes the diborylation of alkynes and arynes, and the tri‐ or tetraborylation of propargyl ethers (see scheme; pin=pinacolato). In the latter cases, the CO bond(s) as well as the CC bond are borylated in one pot. Furthermore, a diborylation product serves as an intermediate in the efficient synthesis of ortho‐terphenyls with pharmacological
(Z)-l,2,3,4-Tetraboryl-2-butene reacted with three molecules of 2,3-dialkylidene-l,5-alkanediol as a single stereoisomer. Preparation and triple addition of the butene can be effected in a single operation.
Discovery and Computational Rationalization of Diminishing Alternation in [<i>n</i>]Dendralenes
作者:Mehmet F. Saglam、Thomas Fallon、Michael N. Paddon-Row、Michael S. Sherburn
DOI:10.1021/jacs.5b11889
日期:2016.1.27
The [n]dendralenes are a family of acyclic hydrocarbons which, by virtue of their ability to rapidly generate structural complexity, have attracted significant recent synthetic attention. [3]Dendralene through [8]dendralene have been previously prepared but no higher member of the family has been reported to date. Here, we describe the first chemical syntheses of the higher dendralenes, [9]dendralene through [12]dendralene. We also report a detailed investigation into the spectroscopic properties and chemical reactivity of the complete family of fundamental hydrocarbons, [3]dendralene to [12]dendralene. These studies reveal the first case of diminishing alternation in behavior in a series of related structures. We also report a comprehensive series of computational studies, which trace this dampening oscillatory effect in both spectroscopic measurements and chemical reactivity to conformational preferences.