Copper catalysed alkynylation of tertiary amines with CaC2 via sp3 C-H activation

 

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC00872K, Communication

Siew Ping Teong, Dingyi Yu, Yin Ngai Sum, Yugen Zhang
A mild and easy-to-handle protocol to produce propargylamines with a terminal alkyne through sp³ C-H bond activation and C-C coupling of tertiary amines and calcium carbide has been developed.

Copper catalysed alkynylation of tertiary amines with CaC2 via sp3 C-H activation

 

Siew Ping Teong,^a   Dingyi Yu,^a   Yin Ngai Sum^a and  Yugen Zhang*^a  

*Corresponding authors

^aInstitute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore
E-mail: ygzhang@ibn.a-star.edu.sg

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC00872K

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC00872K?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

A mild and easy-to-handle protocol to produce propargylamines with a terminal alkyne through catalytic cross-coupling of tertiary amines and calcium carbide has been developed. The reaction proceeds via sp³ C–H bond activation and C–C coupling. Good to excellent yields were obtained for the corresponding propargylamines with both alkyl and aryl substitutions. The development of these functionalized propargylamines with a terminal alkyne group will offer a wider application for the synthesis of natural or pharmaceutical products due to their unique sp C–H reactivity.

N-methyl-N-(prop-2-yn-1-yl)cyclohexanamine (3a) This compound was prepared according to general procedure and isolated by column chromatography (ethyl acetate/hexane = 1/8) to give the product as a light yellow liquid (139 mg, 92%). 1H NMR (400 MHz, CDCl3) δ 3.42 (d, J = 2.4 Hz, 2H, CH2), 2.39 – 2.31 (m, 1H, CH), 2.35 (s, 3H, CH3), 2.19 (t, J = 2.5 Hz, 1H, C≡CH), 1.92 – 1.90 (m, 2H, CH2), 1.78 – 1.75 (m, 2H, CH2), 1.62 – 1.59 (m, 1H, CH2), 1.31 – 1.08 (m, 5H, CH2); 13C NMR (101 MHz, CDCl3) δ 79.8, 72.6, 60.7, 42.9, 38.5, 29.8, 26.0, 25.5; HRMS (EI) m/z calcd. for C 10 H 17 N 151.1361; found 151.1358

/////Copper catalysed alkynylation,  tertiary amines,  CaC2,  sp3 C-H activation

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