钯催化硼-碳和硼-杂原子键构建一锅法合成双官能团化邻-碳硼烷  

Pd-Catalyzed One-Pot Synthesis of Difunctionalized o-Carboranes via Construction of B—C and B—Heteroatom Bonds

作　　者：葛懿修 邱早早[1] 谢作伟[1,2] Ge Yixiu;Qiu Zaozao;Xie Zuowei(Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis,Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,Shanghai 200032;Department of Chemistry,The Chinese University of Hong Kong,Hong Kong,China)

机构地区：[1]中国科学院上海有机化学研究所沪港化学合成联合实验室,上海200032 [2]香港中文大学化学系,中国香港

出　　处：《化学学报》2022年第4期432-437,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(No.92056106);香港研究资助局(No.14305018)资助项目。

摘　　要：碳硼烷是由碳氢和硼氢顶点组成的笼状分子,在医药、能源和材料等领域有着重要应用,但目前在碳硼烷硼顶点引入杂原子取代基的方法还较为有限.基于此,本工作从3-碘-邻-碳硼烷出发,通过钯催化烯基化、金属迁移及后续与杂原子亲核试剂的偶联反应,一锅法构筑硼碳键和硼杂原子键,成功实现了一系列新型3-烯基-4-胺基/烷氧基/烷(芳)硫基-邻-碳硼烷衍生物的合成.Icosahedral carboranes are carbon-boron molecular clusters,sharing many features with benzene such as aromaticity,high thermal and chemical stability.On the other hand,carboranes have their own unique characteristics like spherical geometry and three-dimensional electronic delocalization.These properties render carboranes unique building blocks for various applications ranging from versatile ligands to functional materials to medicine.In this regard,functionalization of carboranes,particularly regioselective functionalization of cage B-vertexes has recently received much attention.Based on our recently developed Pd-catalyzed iodine-migration on o-carborane cage,a Pd-catalyzed regioselective difunctionalization of 3-iodo-o-carborane in a one-pot manner has been achieved to afford a series of 3-alkenyl-4-Nu-o-carboranes(Nu=arylamino,alkoxyl,alkyl and arylthio) in 47%~99% yields.This protocol combines the sequential activation of cage B(3)—I and B(4)—H bonds by Pd migration,as well as further Pd-catalyzed transformation of B(4)—I bond,leading to the construction of B—C and B—Heteroatom bonds.A general procedure for the synthesis of 3-alkenyl-4-Nu-o-carboranes is described as follows:to a tetrahydrofuran(THF) solution(1 mL) of NuH(1.0 mmol) was added base(1.0 mmol) at 0 ℃under an atmosphere of dry nitrogen.The reaction mixture was stirred for another 10 min to obtain the NuM solution(NuM=Ar NHMg Br,base=EtMgBr;NuM=Ar_(2)NLi,base=nBuLi).Another oven-dried Schlenk flask equipped with a stir bar was charged with 3-iodo-o-carborane(1,27 mg,0.1 mmol),Pd(PPh_(3))_(4)(12 mg,0.01 mmol),diphenylacetylene(89 mg,0.5mmol) and dry toluene(1 mL) under an atmosphere of dry nitrogen.The flask was closed,and stirred at 80 ℃ for 72 h.Then,the resulting solution was cooled to 0 ℃,to which was slowly added NuM(0.15 mmol)(NuM=Ar NHMgBr,Ar_(2)NLi,tBu ONa and RSNa).The reaction mixture was warmed to room temperature,and stirred at 80 ℃ for 24 h.After quenching with water(1 mL) and extraction with ethyl acetate(5 mL×3),th

关 键 词：碳硼烷 钯催化 金属迁移 硼-碳键 硼-杂原子键 

分 类 号：O641.4[理学—物理化学]