640280-28-0Relevant articles and documents
Access to Silylated Pyrazole Derivatives by Palladium-Catalyzed C?H Activation of a TMS group
Mistico, Laetitia,Querolle, Olivier,Meerpoel, Lieven,Angibaud, Patrick,Durandetti, Muriel,Maddaluno, Jacques
supporting information, p. 9687 - 9692 (2016/07/14)
A simple and efficient approach to new silylated heterocycles of potential interest in medicinal chemistry is presented. A set of bromophenyl trimethylsilyl pyrazole intermediates can be transformed by direct organometallic routes into two families of regioisomeric iodoaryl substrates; using either arylzinc or aryllithium chemistry, the TMS group remains on the pyrazole ring or translocates to the aryl moiety. These two families can then be efficiently transformed into benzo silino pyrazoles thanks to a single-step cyclization relying on the Pd-catalyzed activation of a non-activated C(sp3)?H bond alpha to a silicon atom. The experimental conditions used, which are fully compatible with the pyrazole ring, suggest that this reaction evolves through a concerted metalation–deprotonation (CMD) mechanism.
Ligand-Enabled Meta-C-H Alkylation and Arylation Using a Modified Norbornene
Shen, Peng-Xiang,Wang, Xiao-Chen,Wang, Peng,Zhu, Ru-Yi,Yu, Jin-Quan
supporting information, p. 11574 - 11577 (2015/09/28)
2-Carbomethoxynorbornene is identified as a more effective transient mediator to promote a Pd(II)-catalyzed meta-C(sp2)-H alkylation of amides with various alkyl iodides as well as arylation with previously incompatible aryl iodides. The use of a tailor-made quinoline ligand is also crucial for this reaction to proceed.
Soft propargylic deprotonation: Designed ligand enables au-catalyzed isomerization of alkynes to 1,3-Dienes
Wang, Zhixun,Wang, Yanzhao,Zhang, Liming
supporting information, p. 8887 - 8890 (2014/07/08)
By functionalizing the privileged biphenyl-2-ylphosphine with a basic amino group at the rarely explored 3′ position, the derived gold(I) complex possesses orthogonally positioned "push" and "pull" forces, which enable for the first time soft propargylic deprotonation and permit the bridging of a difference of >26 pKa units (in DMSO) between a propargylic hydrogen and a protonated tertiary aniline. The application of this design led to efficient isomerization of alkynes into versatile 1,3-dienes with synthetically useful scope under mild reaction conditions.