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

*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

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.
STR1
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
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/////Copper catalysed alkynylation,  tertiary amines,  CaC2,  sp3 C-H activation

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