1098232-41-7Relevant academic research and scientific papers
Factors relevant for the regioselective cyclopolymerization of 1,6-heptadiynes, N,N-dipropargylamines, N,N-dipropargylammonium salts, and dipropargyl ethers by RuIV-alkylidene-based metathesis initiators
Kumar, P. Santhosh,Wurst, K.,Buchmeiser, Michael R.
supporting information; experimental part, p. 387 - 395 (2009/06/28)
The factors relevant for the regioselectivity of insertion of various 1,6-heptadiynes, N,N- dipropargylamines, N,N-dipropargylammonium salts anddipropargyl ethers into different RuIV-alkylidenes, i.e., [R u(CF 3COO)2(IMesH2)(=CHR), (R = 2,4,5-(MeO) 3-C6H2(l1) 2-(2-PrO)-5-NO2-C 6H3 (I3), 2-(2- PrO)-C6H4 (I4)), [Ru(CF3COO)2(1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2- ylidene)(=CH-2-(2-PrO)-5- NO2-C6H3)] (I2), [Ru(CF3COO)2(3-mesityl-1-((1′fl)-1′- phenylethyl)-imidazolin-2-ylidene)(=CH-2-(2-PrO)- C6H4)] (I5) and [Ru(C6F5COO)2(IMesH 2)(=CH-2-(2-PrO)-C6H4)] (I6), (IMesH 2 = 1,3-dimesitylimidazolin-2- ylidene), is described. 13C NMR experiments revealed that all polymers synthesized by the action of I1-I6 consisted virtually solely (>95percent) of five-membered repeat units, i.e., (cyclopent-1-enylene)-1,2-vinylenes, 3,4-(1 H-2,5-dihydropyrrylenium)-3,4- vinylenes, and (2-pentyl-2,5-dihydrofurylene)-3,4-vinylenes, respectively. The 13C NMR-based assignments were supported by the synthesis of model compounds, i.e., (cyclopent- 3-ene-1,1-diyldimethylbis(tris(3,5-dimethoxyphenyl) carboxylate) (MC1) and N-propyl-N-ethyl-2,5-dihydro- pyrrolium tetrafluoroborate (MC2), as well as by ene-yne cross metathesis reactions of 3-(propargyloxy)- 1-octyne (M6) with trimethylallylsilane. In the polymerization of N-ethyl-N,N-dipropargylamine (M9), an intermediate was isolated that shedslight onto the role of heteroatoms in the 4-position of 1,6-heptadiynes in cyclopolymerization. In addition, in the cyclopolymerization of M9 b y I4 the product resulting from backbiting has been isolated and explains for the low polymerization propensity of Ru-alkylidenes for N-alkyl-N,N-dipropargylamines.
