协同亲核取代,称为 S N 2 反应,是合成中用于引入新官能团并构建碳-碳和碳-杂原子键1 的基本有机转化。 S N 2 反应通常涉及亲核试剂对C( sp 3 )−X 键(X=卤素或其他离去基团)的σ* 轨道的背面攻击,导致立体中心2的完全反转。相比之下,电子无偏sp 2乙烯基亲电子试剂上相应的立体反转亲核取代,即协同 S N V(σ) 反应,要罕见得多,并且到目前为止,仅限于精心设计的底物,主要发生在成环过程中3,4 。在这里,我们表明,金属化配合物中提出的应变释放机制可以加速协同的 S N V 反应,从而导致多种有机硼酸酯的通用和立体特异性亚烯基同系物的发展。该方法能够迭代并入多个亚烯基单元,从而产生以其他方式难以制备的交叉共轭多烯。还证明了其在含有多取代烯烃的生物活性化合物的合成中的进一步应用。计算研究表明,方形平面过渡态中空间应变的减少促进了一种不寻常的 S N 2 样协同途径,这解释了这种金属化物
Silver(i)-catalyzed carboxylation of arylboronic esters with CO2
作者:Xiao Zhang、Wen-Zhen Zhang、Ling-Long Shi、Chun-Xiao Guo、Ling-Ling Zhang、Xiao-Bing Lu
DOI:10.1039/c2cc32045b
日期:——
A variety of arylboronic esters were efficiently carboxylated with CO2 using a simple AgOAc/PPh3 catalyst, affording the corresponding carboxylic acids in good yield. This simple and efficient silver(I) catalytic system showed wide functional group compatibility.
Nickel‐Catalyzed 1,2‐Diarylation of Alkenyl Carboxylates: A Gateway to 1,2,3‐Trifunctionalized Building Blocks
作者:Joseph Derosa、Taeho Kang、Van T. Tran、Steven R. Wisniewski、Malkanthi K. Karunananda、Tanner C. Jankins、Kane L. Xu、Keary M. Engle
DOI:10.1002/anie.201913062
日期:2020.1.13
delivers the desired 1,2-diarylated and 1,2-arylalkenylated products with excellent regiocontrol. To demonstrate the synthetic utility of the method, a representative product is prepared on gram scale and then diversified to eight 1,2,3-trifunctionalized building blocks using two-electron and one-electron logic. Using this method, three routes toward bioactive molecules are improved in terms of yield
Direct Vinylation and Difluorovinylation of Arylboronic Acids Using Vinyl- and 2,2-Difluorovinyl Tosylates via the Suzuki−Miyaura Cross Coupling
作者:Thomas M. Gøgsig、Lina S. Søbjerg、Anders T. Lindhardt、Kim L. Jensen、Troels Skrydstrup
DOI:10.1021/jo7027097
日期:2008.5.1
reaction conditions were developed for the Pd(0)-catalyzed Suzuki−Miyaura coupling reaction of aryl boronic acids with a simple electrophilic vinylation reagent, vinyl tosylate, providing access to styrene derivatives in good yields. The easilyaccessible vinyl tosylate represents a stable and less toxic alternative to the vinyl halides and the triflate/nonaflate derivatives. Furthermore, this methodology
The nickel‐catalyzed borylation of aryl2‐pyridyl ethers via the loss of a 2‐pyridyloxy group is described. This method allows a 2‐pyridyloxy group to be used as a convertible directing group in C−H bond functionalization reactions. The nickel catalyst can also borylate arylmethyl 2‐pyridyl ethers, in which the stereochemistry at the benzylic position is retained in the case of chiral secondary benzylic
The Cu(I)-catalyzed ring-opening cross-coupling of an oxabicyclic olefin with an organoboron reagent provides access to cis-2-aryl-1,2-dihydronaphthalen-1-ol derivatives, in contrast to the exclusive trans-selectivity in related Cu-catalyzed reactions with Grignard reagents. DFT calculations suggest that the reaction possibly proceeds via boronic ester by-product assisted ring-opening as an alternative