Assignment of cis-trans Geometry in Diastereomeric 2-Benzyl-4-methyl-1,3,2-dioxaphosphorinans and their 2-Oxo- and 2-Seleno-Derivatives

1975 ◽  
Vol 30 (9-10) ◽  
pp. 710-715 ◽  
Author(s):  
W. J. Stec ◽  
K. Lesiak ◽  
D. Mielczarek ◽  
B. Stec

MICHAELIS-ARBUSOV reaction of diastereoisomeric 2-methoxy-4-methyl-1,3,2-dioxaphosphorinans with benzyl halides is non-stereospecific. Cis- and trans-2-benzyl-2-oxo-4-methyl-1,3,2-dioxaphosphorinans were separated and analysed by means of IR, 31P and 13C NMR spectroscopy. 2-Benzyl-2-seleno-4-methyl-1,3,2-dioxaphosphorinans were synthesized and stereospecifically converted to 2-oxo-analogues. Stereochemistries are assigned to the geometrical isomers of all new compounds described in this paper. Application of direct spin-spin coupling constant values for structural elucidation is emphasized.

1996 ◽  
Vol 74 (8) ◽  
pp. 1524-1525 ◽  
Author(s):  
Ted Schaefer ◽  
Guy M. Bernard ◽  
Frank E. Hruska

An excellent linear correlation (r = 0.9999) exists between the spin–spin coupling constants 1J(1H,13C), in benzene dissolved in four solvents (R. Laatikainen et al. J. Am. Chem. Soc. 117, 11006 (1995)) and Ando's solvation dielectric function, ε/(ε – 1). The solvents are cyclohexane, carbon disulfide, pyridine, and acetone. 1J(1H,13C)for gaseous benzene is predicted to be 156.99(2) Hz at 300 K. Key words: spin–spin coupling constants, 1J(1H,13C) for benzene in the vapor phase; spin–spin coupling constants, solvent dielectric constant dependence of 1J(1H,13C) in benzene; benzene, estimate of 1J(1H,13C) in the vapor; nuclear magnetic resonance, estimate of 1J(1H,13C) in gaseous benzene.


1989 ◽  
Vol 25 (3) ◽  
pp. 338-341
Author(s):  
L. M. Kapkan ◽  
A. Yu. Chervinskii ◽  
T. M. Pekhtereva ◽  
Yu. I. Smirnov ◽  
A. F. Dmitruk

1986 ◽  
Vol 64 (8) ◽  
pp. 1602-1606 ◽  
Author(s):  
Ted Schaefer ◽  
Rudy Sebastian ◽  
Glenn H. Penner ◽  
S. R. Salman

The through-space or proximate nuclear spin–spin coupling constant, 5J(F,CH3) = 5J, between methyl protons and ring fluorine nuclei in alkylfluorobenzenes is postulated as [Formula: see text] θ being the torsional angle for the [Formula: see text] bond. A and B are obtained from the known internal rotational behaviour in 2,6-difluoroethylbenzene and the corresponding cumene derivative. The parameterization is tested on the observed 5J in derivatives of 2,4,6-tri-tert-butyl- and 2,4,6-tri-isopropyl-fluorobenzene, in 2-chloro-6-fluoroisopropylbenzene, 2,6-difluoro-α-methylstyrene, and N-methyl-8-fluoroquinolinium halides. A prediction is made for 5J in 2,6-difluoro-tert-butylbenzene. It appears that the present parameterization allows the derivation of approximate torsional potentials from proximate couplings, for example in α,α-dimethyl-2,6-difluorobenzyl alcohol.


1988 ◽  
Vol 92 (11) ◽  
pp. 3056-3059 ◽  
Author(s):  
Jens Oddershede ◽  
Jan Geertsen ◽  
Gustavo E. Scuseria

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