N-Propargylamides with one, two, and three phenylgroups at the α-position of the carboxyl group [HC≡CCH2NHCOR; 1, R = C(CH3)2C6H5; 2, R = CCH3(C6H5)2; 3, R = C(C6H5)3] were polymerized with a rhodium catalyst, (nbd)Rh+B-(C6H5)4 (nbd = 2,5-norbornadiene), to obtain the corresponding polymers in 85−91% yields. Poly(1) possessed a moderate molecular weight (Mn = 6300) and was thoroughly soluble in chloroform
Ñ -Propargylamides具有一个,两个,并且在三个苯基α羧基[HC≡CCH的-位2 NHCOR; 1,R = C(CH 3)2 C 6 H 5;R = C(CH 3)2 C 6 H 5。2,R = CCH 3(C 6 H 5)2 ; 3,R = C(C 6 H ^ 5)3 ]与铑催化剂进行聚合,(NBD)的Rh +乙-(C 6 H ^ 5)4(nbd = 2,5-降冰片二烯),以85-91%的产率获得相应的聚合物。Poly(1)具有中等分子量(M n = 6300),并且完全溶于氯仿和二氯甲烷。另一方面,poly(2)和poly(3)不能完全溶于溶剂。氯仿可溶部分的M n小于3000。这三种聚合物在氯仿中的二级结构通过紫外可见光谱法在不同温度下进行了检查。发现即使在60°C时,只有poly(1)可以采用螺旋构象。通过单体2或3与HC≡CNH的共聚2 CO(CH 2)4 H(4)
A protocol for amide bond formation with electron deficient amines and sterically hindered substrates
作者:Maria E. Due-Hansen、Sunil K. Pandey、Elisabeth Christiansen、Rikke Andersen、Steffen V. F. Hansen、Trond Ulven
DOI:10.1039/c5ob02129d
日期:——
A protocol for amide coupling by in situ formation of acyl fluorides and reaction with amines at elevated temperature has been developed and found to be efficient for coupling of sterically hindered substrates and electron deficient amines where standard methods failed.
Dual hydrogen bond donation, one from side-arm amide, and another from substrate or acid additive, enables Au(i)–Cl bond activation and gold(i)-catalysis.