63720-98-9Relevant articles and documents
Comparative spectroscopic and theoretical studies on the conformation of some α-diethoxyphosphoryl carbonyl compounds and their α-ethylsulfonyl analogues
Olivato, Paulo R.
, p. 97 - 102 (2001)
Comparative vco IR analysis of β-carbonylphosphonates [XC(O)CH2P(O)(OR)2: X = Me 1, Ph 2, OEt 3, NEt2 4 and SEt 5; R = Et] (series I) and β-carbonylsulfones [XC(O)CH2SO2R: X = Me 6, Ph 7, OEt 8, NEt2 9 and SEt 10; R = Et] (series II) along with ab initio 6-31 G** calculations on la and 6a (R = Me) suggest the existence of only a single gauche conformer for series I. The negative carbonyl frequency shifts for both series follow approximately the electron-affinities of the π*co orbital of the parent compounds MeC(O)X 11-15. The less positive asymmetric sulfonyl frequency shifts (ΔvSO2) for II in relation to the phosphoryl frequency shifts (ΔvPO) for I and the larger negative carbonyl frequency shifts for II with respect to the corresponding values for I are in line with the upfield 13C NMR chemical shifts of the carbonyl carbon for II compared to I. These trends agree with the shorter O(SO2) ...C(CO) contact in comparison with the O(PO) ... C(CO) one and are discussed in terms of Olp→π*co charge transfer and electrostatic interactions, which are stronger for series II than for I, indicating that the sulfonyl oxygen atom is a better electron donor than the phosphoryl oxygen atom. Intrinsic geometrical parameters of O=S-CH2 and O=P-CH2 moieties seem to be responsible for this behaviour as indicated by X-ray study and ab initio calculations of dialkyl (methylsulfonyl)methylphosphonate MeSO2CH2P(O)(OR)2(R = Et l8, Me 18a). The Royal Society of Chemistry 2001.
