by its addition to aldehydes in the presence of boron trifluoride etherate yielded rather stable β-hydroxyalkylboronates (5). The thermal dehydroxyboronation or the alkaline hydrogen peroxide oxidation of 5 gave the corresponding alkenes (6) or 1,2-alkanediols (7) in high yields. The reaction provides a simple procedure for the olefination or the hydroxymethylation of aldehydes.
用Knochel的(二烷氧基硼烷基)甲基锌试剂(2)和CuCN•2LiCl在THF中原位制备[(Me 2 C)2 O 2 BCH 2 ] Cu(CN)ZnI(3),然后将其添加到乙醛中。三氟化硼醚化物的存在会产生相当稳定的β-羟烷基硼酸酯(5)。热dehydroxyboronation或的碱性过氧化氢的氧化5得到相应的烯烃(6)或1,2-烷二醇(7以高收率)。该反应提供了用于醛的烯化或羟甲基化的简单程序。
Hole-transfer catalyzed reaction: One-electron oxidation as a strategy for the selective cyclopropanation of π bonds
作者:Gholam A. Mirafzal、Albena M. Lozeva、Jeffrey A. Olson
DOI:10.1016/s0040-4039(98)02163-7
日期:1998.12
The cyclopropanation of alkenes, dienes and trienes with ethyl diazoacetate catalyzed by tris(4-bromophenyl)aminium hexachloroantimonate have been studied. The efficiency and selectivity of cyclopropanation is based solely upon, and is highly sensitive to, the ease of ionization of π bonds in the substrate. Simple double bonds such as norbornene and 1-octene are not amenable to cyclopropanation via
Control of Selectivity through Synergy between Catalysts, Silanes, and Reaction Conditions in Cobalt-Catalyzed Hydrosilylation of Dienes and Terminal Alkenes
作者:Balaram Raya、Stanley Jing、Vagulejan Balasanthiran、T. V. RajanBabu
DOI:10.1021/acscatal.6b03373
日期:2017.4.7
with 2 equiv of NaEt3BH at −78 °C in toluene to generate a catalyst that effects highly selective anti-Markovnikov hydrosilylation of the terminal double bond in 1,3- and 1,4-dienes. Primary and secondary silanes such as PhSiH3, Ph2SiH2, and PhSi(Me)H2 react with a broad spectrum of terminal dienes without affecting the configuration of the other double bond. When dienes conjugated to an aromatic ring