A Micellar Catalysis Strategy for Suzuki–Miyaura Cross-Couplings of 2-Pyridyl MIDA Boronates: No Copper, in Water, Very Mild Conditions
摘要:
Suzuki-Miyaura (SM) cross-couplings of 2-pyridyl MIDA boronates can be successfully carried out in the complete absence of copper by attenuation of the Lewis basicity associated with the pyridyl nitrogen using selected substituents (e.g., fluorine or chlorine) on the ring. This strategy imparts additional synthetic options compared with existing approaches based on the use of Lewis acids or N-oxides. Thus, access to highly valued 2-substituted pyridyl rings via an initial Suzuki-Miyaura coupling can be followed by dehalogenation, SNAr reactions, or a second SM coupling to arrive at 2,6-disubstituted pyridyl arrays, all run in a single pot, enabled by micellar catalysis in water. Accessing targets within drug-like space is demonstrated in a four-step, one-pot sequence. Computational data suggest that the major role being played by electron-withdrawing substituents in promoting these cross-couplings without the need for copper is to slow the rates of protodeboronation of intermediate 2-pyridylboronic acids.
Hiyama Cross-Coupling of Chloro-, Fluoro-, and Methoxypyridyltrimethylsilanes: Room-Temperature Novel Access to Functional Bi(het)aryl
作者:Philippe Pierrat、Philippe Gros、Yves Fort
DOI:10.1021/ol047482u
日期:2005.2.1
pyridyltrimethylsilanes allowed us to perform efficient Hiyama cross-coupling with various (het)arylhalides. The reactions proceeded smoothly at room temperature leading to the corresponding functional bis(het)aryl in fair to excellent yields. The presence of pyridine nitrogen alpha to the trimethylsilyl group was requisite to achieve the cross-coupling. [Reaction: see text]
Nickel-catalyzed enantioselective α-heteroarylation of ketones <i>via</i> C–F bond activation to construct all-carbon quaternary stereocenters
作者:Xiaodong Gu、Kexin Liu、Limin Yang、Chengyi Xie、Mingliang Li、Jun (Joelle) Wang
DOI:10.1039/d2sc03409c
日期:——
to provide the corresponding products containing all-carbon quaternary stereocenters in good yields (up to 99% yield) and high ee values (up to 99% ee). In addition, drug molecule donepezil could also be compatible under the reaction conditions to afford late-stage diversification of pharmaceuticals.