Conjugated aldehydes and ketones undergo reaction with Me2PhSiBpin (pin: pinacolato) catalyzed by Au nanoparticles supported on TiO2 forming exclusively the β-borylation products, via the intermediate formation of the labile silaboration adducts. This chemoselectivity pathway is complementary to the so far known analogous reaction catalyzed by other metals, where β-silylation occurs instead. β-Borylation
Copper‐Photocatalyzed Hydroboration of Alkynes and Alkenes
作者:Mingbing Zhong、Yohann Gagné、Taylor O. Hope、Xavier Pannecoucke、Mathieu Frenette、Philippe Jubault、Thomas Poisson
DOI:10.1002/anie.202101874
日期:2021.6.21
photocatalytic hydroboration of alkenes and alkynes is reported. The use of newly-designed copper photocatalysts with B2Pin2 permits the formation a boryl radical, which is used for hydroboration of a large panel of alkenes and alkynes. The hydroborated products were isolated in high yields, with excellent diastereoselectivities and a high functional group tolerance under mild conditions. The hydroboration reactions
报道了烯烃和炔烃的光催化硼氢化反应。使用新设计的铜光催化剂和 B 2 Pin 2可以形成硼基自由基,该自由基可用于大量烯烃和炔烃的硼氢化反应。硼氢化产物以高产率分离,在温和条件下具有优异的非对映选择性和高官能团耐受性。硼氢化反应是在连续流动条件下开发的,以证明其合成效用。研究了反应机理,并提出了原位形成的硼酸盐和处于激发态的铜光催化剂之间的氧化反应,以形成硼基自由基。
Copper-Catalyzed Tandem Asymmetric Borylation of β-Chloroalkyl Aryl Ketones and Related Compounds
作者:Quanbin Jiang、Tenglong Guo、Zhengkun Yu
DOI:10.1002/cctc.201402823
日期:2015.2
The Cu‐catalyzed, one‐pot tandem (asymmetric) borylation of β‐chloroalkyl aryl ketones via the in situ generated acyclic enones with bis(pinacolato)diboron was achieved efficiently to reach up to 97 % yield and 99 % enantioselectivity for the formal sp3 CCl borylation products. The present methodology provides an efficient alternative route to (chiral) alkylboron compounds.
The cleavage and transformation of alkenyl C(sp2)–N bonds is a significant synthetic challenge. Herein we described an unprecedented nickel-catalyzed reductive borylation of enaminones to synthesize β-ketone boronic esters. Notably, B2pin2 played the dual role in this process, and water served as a hydrogen source, which was transferred to target products. The air-stable nickel catalyst was applied
β‐Functionalized and α,β‐Difunctionalized Ketones from 1‐Arylallylic Alcohols via Dipotassio α,β‐Dianion Intermediates
作者:Rikuo Hayashi、Kaori Ando、Taro Udagawa、Masahiro Sai
DOI:10.1002/adsc.202201047
日期:2023.3.21
(TMSCH2K). The reaction proceeded via the formation of the highly nucleophilic dipotassio α,β-dianion as the key intermediate, which served as a metalhomoenolate equivalent. This protocol also allowed the one-pot synthesis of α,β-difunctionalized ketones using two different electrophiles, thus demonstrating its synthetic advantages over other protocols involving metalhomoenolates.