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Conformational and Configurational Dynamics of a Highly Fluorinated Hydrazone

“…Conformational Structure and Dynamics. The 19 F NMR spectrum in CDCl 3 of the mixture comprises three signals for each isomer, but we found that in CD 3 CN each of the signals for the E -isomer, but not the Z , is doubled. The geminal CF 3 groups in the E form appear at δ −59.8 and −61.3.…”

“…2 H -Perfluoro-2-methyl-3-pentanone Hydrazone (2). To a stirred solution of alkene 1 (9 g, 30 mmol) in acetic acid (35 mL) was added hydrazine hydrate (3 g, 60 mmol) dropwise while maintaining the reaction mixture temperature at 0−5 °C. Vigorous stirring was continued at that temperature for 1 h, and then the mixture was heated at 45 °C for 2 h. The reaction mixture was poured in methylene chloride (100 mL), washed with water (100 mL), with saturated sodium bicarbonate solution until it was free from acetic acid, and with water again.…”

“…Furin et al have reported that treatment of perfluoro-2-methyl-2-pentene ( 1 ) with hydrazine hydrate in acetic acid yields hydrazone 2 as a 2.1:1 mixture of Z - and E -isomers, respectively, characterized by 1 H, 13 C, and 19 F NMR spectra . We repeated the preparation of 2 to study the interesting transformation it undergoes upon treatment with triethylamine .…”

Synthesis, Mechanism of Formation, and Dynamics of a Highly Fluorinated Methylenecyclobutene

“…Prepared from alkene 10 , hydrazone 1 is a roughly 2:1 mixture of E - and Z -isomers. , When it is treated with triethylamine at room temperature, a small amount of 6 is obtained from the E -isomer, but the principal product is Z -vinyl fluoride 11 (Scheme ) . Alkene 11 is formed readily from the E - but only slowly from the Z -hydrazone isomer.…”

“…As a minor observation at the end of an interesting paper on the synthesis of highly fluorinated heterocycles, Furin et al reported that hydrazone 1 was transformed by triethylamine into a mixture of cyclobutadienes 2 and 3 . The volatile liquid mixture they obtained was characterized by 13 C NMR, 19 F NMR, MS, and HRMS.…”