Determination of theZ¹H NMR chemical shift substituent parameters for the sulfinyl chloride and sulfinate ester functionalities

Abstract

Using established and new 1 H NMR data for sulfinate esters and sulfinyl chlorides, the parameters required for predicting position-dependent alkene 1 H NMR chemical shifts of vinylic sulfinate esters and vinylic sulfinyl chlorides have been obtained. Standard deviations of the new Z parameters lie in the range 0.08 to 0.15 ppm. Sulfinyl chloride and cyclohexyl sulfinate derivatives of (E) and (Z )-2-cyanoethenesulfinic acids have been prepared for the first time.The alkene additivity chemical shift rule Eq. (1) has long been used by organic chemists to interpret 1 H NMR spectra [1][2][3][4]. When a double bond configuration is uncertain, application of the rule, using tabulated chemical shift influences of substituents (Z values) usually allows a rapid and tentative, if not unequivocal, assignment of double bond geometry.Since its introduction [1], the table of substituent constants for common alkene substituents has found its way into several organic spectroscopy reference books. However, such entries are usually a reproduction of the original work [2-4], despite the emergence of new Z parameters for less common functional groups [5][6][7][8].Sulfinyl chloride and sulfinate ester functional groups are part of modern investigations [9, 10] and, as such, double bonded compounds bearing these substituents are of interest to us [11][12][13][14][15][16] and to others [17][18][19][20][21][22][23][24][25][26][27]. Unfortunately the alkene additivity rule is unavailable for investigators in this area due to the lack of appropriate substituent constants.

1H chemical shifts in NMR. Part 27: proton chemical shifts in sulfoxides and sulfones and the magnetic anisotropy, electric field and steric effects of the SO bond

“…However, it serves as a useful approximation to aid in the assignment of 1 H NMR spectra. A similar study was conducted for the substituent parameters for the sulfinyl chloride and sulfinate ester functional groups, [9] again including only short-range effects.…”