Development of Enantiospecific Coupling of Secondary and Tertiary Boronic Esters with Aromatic Compounds
作者:Marcin Odachowski、Amadeu Bonet、Stephanie Essafi、Philip Conti-Ramsden、Jeremy N. Harvey、Daniele Leonori、Varinder K. Aggarwal
DOI:10.1021/jacs.6b03963
日期:2016.8.3
functional groups (esters, azides, nitriles, alcohols, and ethers). The reaction also worked well with other electron-rich heteroaromatics and 6-membered ring aromatics provided they had donor groups in the meta position. Conditions were also found under which the B(pin)- moiety could be retained in the product, ortho to the boron substituent. This protocol, which created a new C(sp2)–C(sp3) and an adjacent
仲硼酸酯与 sp2 亲电试剂的立体有择交叉偶联(Suzuki-Miyaura 反应)是合成中长期存在的问题,但在使用钯催化的特定情况下已经取得了进展。然而,目前无法实现与叔硼酸酯的相关偶联。为了解决这一普遍问题,我们专注于利用芳基锂和硼酸酯之间形成的硼酸盐络合物的反应性的替代方法。我们推断,随后添加氧化剂或亲电子试剂会分别从芳环中去除电子或以 Friedel-Crafts 型方式反应,产生阳离子物质,这将引发硼取代基的 1,2-迁移,创建新的 C-C 键。消除(在前一种情况下,在进一步氧化之前)将导致重新芳构化,从而立体特异性地产生偶联产物。最初的工作是用 2-furyllithium 检查的。尽管测试的氧化剂不成功,但亲电试剂,特别是 NBS,使得偶联反应能够以良好的收率与范围广泛的仲和叔硼酸酯发生偶联反应,具有不同的空间需求和官能团(酯、叠氮化物、腈、醇和醚) )。该反应也适用于其他富电子杂芳烃和