Stereoselective Formation of Trisubstituted Vinyl Boronate Esters by the Acid-Mediated Elimination of α-Hydroxyboronate Esters
作者:Weiye Guan、Alicia K. Michael、Melissa L. McIntosh、Liza Koren-Selfridge、John P. Scott、Timothy B. Clark
DOI:10.1021/jo500773t
日期:2014.8.1
trisubstituted vinyl boronate esters with moderate to good yields and selectivity. Addition of tosic acid to the crude diboration products provides the corresponding vinyl boronate esters upon elimination. The trisubstituted vinyl boronate esters are formed as the (Z)-olefin isomer, which was established by subjecting the products to a Suzuki–Miyaura coupling reaction to obtain alkenes of known geometry
铜催化酮的二硼化,然后是酸催化的消除,导致形成 1,1-二取代和三取代乙烯基硼酸酯,具有中等至良好的产率和选择性。将甲苯磺酸加入粗二硼化产物中,消除后得到相应的硼酸乙烯酯。三取代的乙烯基硼酸酯形成为 ( Z )-烯烃异构体,这是通过将产物进行 Suzuki-Miyaura 偶联反应以获得已知几何形状的烯烃来建立的。
Vinylidenation of Organoboronic Esters Enabled by a Pd‐Catalyzed Metallate Shift
作者:Mark D. Aparece、Chenpeng Gao、Gabriel J. Lovinger、James P. Morken
DOI:10.1002/anie.201811782
日期:2019.1.8
Organoboron "ate" complexes undergo a net vinyl insertion reaction to give 1,1-disubstituted alkenyl boronic esters when treated with stoichiometric allylacetate and a palladium catalyst. Reactions that employ vinyllithium afforded good to excellent yields after one hour, while reactions that employ vinylmagnesium chloride furnished modest to good yields after 18 hours.
Palladium-catalyzed Suzuki-type couplings of 3-pyridyl triflates with alkenylpinacol boronates proceed in good to excellent yields. Optimized conditions use Pd(PPh3)4 (10 mol%) as catalyst with K3PO4 (3 equiv) as base in 1,4-dioxane.