undergo [2+2+2] cyclotrimerization with nitriles in the presence of a catalytic amount of the ruthenium complex Cp*RuCl(cod) (10 mol%) to afford the corresponding halopyridines under ambient conditions in good isolated yields (up to 90%). The halopyridines are formed as two separable regioisomers. This is the first example of a direct synthesis of halopyridines from haloalkynes and nitriles.
Alkynyl chlorides, bromides, and iodides have been tested as [2 + 2 + 2] cycloaddition partners using CpCo(CO)(dimethylfumarate) and Cp*Ru(cod)Cl as precatalysts. A series of cocyclizations between diynyl dihalides and alkynes, as well as intramolecular cycloadditions of triynyl dihalides, has been carried out. While this study confirmed the versatility of the ruthenium complex with all kinds of halides
Cp*Co(<scp>iii</scp>)-Catalyzed oxidative [5+2] annulation: regioselective synthesis of 2-aminobenzoxepines <i>via</i> C–H/O–H functionalization of 2-vinylphenols with ynamides
作者:Xiang-Lei Han、Xu-Ge Liu、E Lin、Yunyun Chen、Zhuangzhong Chen、Honggen Wang、Qingjiang Li
DOI:10.1039/c8cc06807k
日期:——
A Cp*Co(III)-catalyzed [5+2] C–H annulation reaction of 2-vinylphenols with ynamides was developed. The reaction led to the efficient synthesis of valuable 2-aminobenzoxepines in high regioselectivity. Mild reaction conditions, good functional group tolerance, and moderate to good yields were observed. The synthetic utility was demonstrated by a gram-scale synthesis and further transformations of the
Homogeneous and Nanoparticle Gold-Catalyzed Hydrothiocyanation of Haloalkynes
作者:Xiaojun Zeng、Bocheng Chen、Zhichao Lu、Gerald B. Hammond、Bo Xu
DOI:10.1021/acs.orglett.9b00728
日期:2019.4.19
homogeneous and heterogeneous nanoparticle gold-catalyzed addition of sulfur nucleophiles to alkynes was developed. More specifically, gold-catalyzed hydrothiocyanation of haloalkynes gave good yields and good stereoselectivity of vinyl thiocyanates. Furthermore, a sulfur-based gold catalyst (PPh3AuSCN) has shown a unique reactivity in gold-catalyzed reactions such as the cyclization of N-propargylic amides
Copper Salt-Catalyzed Azide-[3 + 2] Cycloadditions of Ynamides and Bis-Ynamides
作者:Xuejun Zhang、Hongyan Li、Lingfeng You、Yu Tang、Richard P. Hsung
DOI:10.1002/adsc.200600404
日期:2006.11
A one-pot synthesis of amide-substituted triazoles from alkyl bromides and ynamides is described here along with syntheses of novel bis-ynamides and their applications in [3+2] cycloadditions with azides to construct unique bis-triazoles.