Copper-Catalyzed Decarboxylative Radical Silylation of Redox-Active Aliphatic Carboxylic Acid Derivatives
作者:Weichao Xue、Martin Oestreich
DOI:10.1002/anie.201706611
日期:2017.9.11
A decarboxylative silylation of aliphatic N‐hydroxyphthalimide (NHPI) esters using Si−B reagents as silicon pronucleophiles is reported. This C(sp3)−Si cross‐coupling is catalyzed by copper(I) and follows a radical mechanism, even with exclusion of light. Both primary and secondary alkyl groups couple effectively, whereas tertiary alkyl groups are probably too sterically hindered. The functional‐group
Palladium-Catalyzed Cross-Coupling of Monochlorosilanes and Grignard Reagents
作者:Bojan Vulovic、Andrew P. Cinderella、Donald A. Watson
DOI:10.1021/acscatal.7b03465
日期:2017.12.1
of the Si–Cl bond (113 kcal/mol) and is a rare example of a transition-metal catalyzed process involving its activation. Because of the availability of both chlorosilanes and organomagnesium halide reagents, this method allows for the preparation of a wide range of alkyl and aryl silanes.
Bench-Stable Stock Solutions of Silicon Grignard Reagents: Application to Iron- and Cobalt-Catalyzed Radical C(sp<sup>3</sup>
)-Si Cross-Coupling Reactions
作者:Weichao Xue、Ryosuke Shishido、Martin Oestreich
DOI:10.1002/anie.201807640
日期:2018.9.10
the preparation of silicon‐based magnesiumreagents is reported. The MgBr2 used in the lithium‐to‐magnesium transmetalation step is generated in situ from 1,2‐dibromoethane and elemental magnesium in hot THF. No precipitation of MgBr2 occurs in the heat, and transmetalation at elevated temperature leads to homogeneous stock solutions of the silicon Grignard reagents that are stable and storable in the
Palladium-Catalyzed Cross-Coupling of Silyl Electrophiles with Alkylzinc Halides: A Silyl-Negishi Reaction
作者:Andrew P. Cinderella、Bojan Vulovic、Donald A. Watson
DOI:10.1021/jacs.7b04364
日期:2017.6.14
the first example of a silyl-Negishi reaction between secondary zinc organometallics and silicon electrophiles. This palladium-catalyzed process provides direct access to alkyl silanes. The delicate balance of steric and electronic parameters of the employed DrewPhos ligand is paramount to suppressing isomerization and promoting efficient and selective cross-coupling.
The reaction of unactivated secondary and primary alkyl chlorides as well as primary alkyl triflates with silyl lithium reagents to access tetraorganosilanes is reported. These nucleophilic substitutions proceed in the absence of any transition metal catalyst under mild conditions in moderate to very good yields. The silyl lithium reagents are readily generated from the corresponding commercially available