DEVELOPMENT OF EFFICIENT ORGANIC SYNTHESIS INVOLVING ORGANOBORANE AND ORGANOZINC PROMOTED BY TRANSITION METAL CATALYSIS

三乙基硼烷通过在烯丙基C-O键上氧化加成Pd(0)，激活烯丙醇形成π-烯丙基钯关键中间体，实现两亲性烯丙基化反应。Pd催化烯丙醇、末端炔和有机硼烷的三组分偶联反应生成(E)-1-取代的2-烷基- 1,4 -戊二烯，在乙炔末端碳上进行双烯丙基化和烷基化。双二烯与乙炔和有机硼烷发生类似的多组分偶联反应，涉及双二烯的环化。形成反式烯丙基戊二烯环和杂环化合物。此外，钯催化剂与三乙基硼烷的组合有效地促进3-羟基-4-戊烯酸通过β-乙烯基氧杂环戊酮进行β-脱羧C-C键裂解反应，提供共轭二烯和二氧化碳。

Triethylborane activates allylic alcohols to formπ-allylpalladium key intermediates by oxidative addition of Pd(0) toward allylic C-O bonds and achieves amphiphilic allylations. Pd catalyzes three-component coupling reaction of allylic alcohol, terminal alkyne, and organoborane to provide(E)-1-substituted 2-alkyl-1, 4-pentadiene involving geminal allylation and alkylation at the acetylenic terminal carbon. Bis-diene undergoes the similar multi-component coupling reaction with acetylene and organoborane involving cyclization of bis.π-allypalladium to form trans-allyl pentadienyl cyclic and hetrocyclic compounds. Furthermore, a combination of Pd catalyst and triethylborane effectively promotes 3-hydroxy-4-pentenoic acid to undergoβ-decarboxylative C-C bond cleavage reaction viaβ-vinyloxapalladacyclopentanone to provide conjugated diene and carbon dioxide.