Structures and Rotational Barriers of a Diiodobinorsnoutane: Energetic Preference for Gauche Conformation

Autor:	Mark A. Forman, Caitlin A. Moran, James E. Hall, Don E. Pivonka, Joseph P. Herres, John P. McCauley, Steven Wesolowski
Rok vydání:	2016
Předmět:	Steric effects 010405 organic chemistry Gauche effect Stereochemistry Chemistry Organic Chemistry Alkane stereochemistry Density functional theory 010402 general chemistry 01 natural sciences 0104 chemical sciences
Zdroj:	The Journal of Organic Chemistry. 81:6862-6866
ISSN:	1520-6904 0022-3263
DOI:	10.1021/acs.joc.6b01204
Popis:	The diiodobinorsnoutane, bi(5-iodopentacyclo[4.3.0.0(2,4).0(3,8).0(5,7)]non-4-yl) (5), exists in a sterically hindered gauche conformation rather than an anti or an averaged (freely rotating) C2v structure. Density functional theory (DFT) predictions place the gauche conformation 11 kcal/mol more stable than the anti conformation with a barrier of 17 kcal/mol connecting the minima. These are consistent with variable-temperature NMR (17.1 ± 0.8 kcal/mol) estimates and X-ray analysis. Predictions of the torsional profiles of the yet-unsynthesized bromo-, chloro-, and fluoro- analogues show a progressive lowering of the barriers.
Databáze:	OpenAIRE
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