A Heterogeneous Iridium Catalyst for the Hydroboration of Pyridines
作者:Jessica Rodriguez、Matthew P. Conley
DOI:10.1021/acs.orglett.2c01859
日期:2022.7.1
(cod)Ir(py)Cl (cod = 1,5-cyclooctadiene; py = pyridine) to form [Ir(cod)py][SZO] (1) and Me3SiCl. 1 can also be formed in reactions of phosphonium functionalized SZO and [Ir(cod)(OSi(OtBu)3]2, which forms [Ir(cod)P(tBu)2Ph][SZO] (2), followed by reaction with pyridine to form 1. FTIR and 15N1H} MAS NMR spectroscopy are consistent with coordination of pyridine in 1 to an electrophilic iridium. 1 is moderately
用类硅离子封端的硫酸化氧化锆 (SZO) 与 (cod)Ir(py)Cl (cod = 1,5-环辛二烯;py = 吡啶) 反应形成 [Ir(cod)py][SZO] ( 1 )和 Me 3 SiCl。1也可以在鏻官能化 SZO 和 [Ir(cod)(OSi(O t Bu) 3 ] 2的反应中形成,其形成 [Ir(cod)P( t Bu) 2 Ph][SZO] ( 2 ),然后与吡啶反应形成1。FTIR 和15 N 1 H} MAS NMR 光谱与1中的吡啶与亲电子铱的配位一致。1在吡啶的去芳烃硼氢化反应中具有中等活性。该反应的主要产物是 1,2-二氢吡啶,它在较长的反应时间内转化为 1,4-二氢吡啶产物。1催化多种取代吡啶的脱芳烃硼氢化反应,并且对吡嗪和N-甲基咪唑也有反应性。
Dearomatizing conversion of pyrazines to 1,4-dihydropyrazine derivatives via transition-metal-free diboration, silaboration, and hydroboration
Pyrazines and substituted pyrazines undergo addition of boron reagents having B–B, Si–B, and H–B bonds under transition-metal-free conditions, leading to high-yield synthesis of N-borylated 1,4-dihydropyrazines and 1,2,3,4-tetrahydropyrazine.