The present invention provides a compound represented by the following formula (I) or its pharmaceutically acceptable salt:
[wherein, R
1
represents optionally substituted C
1-4
alkyl, n shows integer of 1 to 4, R
2
represents optionally substituted C
1-4
alkyl or hydrogen atom, R
3
represents optionally substituted C
1-4
alkyl, R
4a
, R
4b
, R
4c
, and R
4d
, similarly or differently, represent optionally substituted C
6-14
aryl, optionally substituted C
1-4
alkyl, or hydrogen atom and the like, A represents optionally substituted C
6-14
aryl or optionally substituted 5 to 11 membered heteroaryl].
Arene CHO Hydrogen Bonding: A Stereocontrolling Tool in Palladium-Catalyzed Arylation and Vinylation of Ketones
作者:Zhiyan Huang、Li Hui Lim、Zuliang Chen、Yongxin Li、Feng Zhou、Haibin Su、Jianrong Steve Zhou
DOI:10.1002/anie.201300621
日期:2013.4.26
Weak is powerful: For the arylation of tin enolates, the palladium catalyst engages in weak CHOhydrogen bonds to control stereoselectivity (see scheme). Similar catalysts capable of NHOhydrogenbonding also works well.
Access to Cycloalkeno[<i>c</i>]-Fused Pyridines via Pd-Catalyzed C(sp<sup>2</sup>)–H Activation and Cyclization of <i>N</i>-Acetyl Hydrazones of Acylcycloalkenes with Vinyl Azides
A novel Pd(II)-catalyzed vinylic C-H activation and cyclization has been developed, reacting a series of small, medium, and large N-acetyl hydrazones of acylcycloalkenes with vinyl azides to access diverse cycloalkeno[c]-fused pyridine scaffolds. This protocol provides progress in C(sp2)-H bond activation of medium to large cycloalkenes, and the target products can be obtained in a specific regioselectivity with good functional group tolerance and a broad substrate scope.
Henbest et al., Journal of the Chemical Society, 1952, p. 1154,1158