Synthesis of New Phosphorus Ylides: Spectroscopic and X-ray Structural Studies

Abstract

Stable phosphoranes, Ar(3)P = CHCOR (R = C(6)H(5), C(6)H(4)NO(2), C(6)H(4)OCH(3), CH 3, OCH(2)C(6)H(5); Ar = p-tolyl or phenyl), have been C-acylated by acetic anhydride to obtain new types of phosphorus ylides. Synthesis and characterization of six phosphorus ylides of the type Ar(3)PC(COCH(3))(COR) are reported. The reaction of {(p-tolyl)(3)PCHCOC(6)H(5)} (I),{(p-tolyl)(3)PCHCOC(6)H(4)NO(2)} (II), {Ph(3)PCHCOC(6)H(4)NO(2)} (III), {Ph(3)PCHCOC(6)H(4)OCH(3)} (IV), {(p-tolyl)(3)PCHCOCH(3)} (V), and {Ph(3)PCHCOOCH(2)C(6)H(5)} (VI) with acetic anhydride in dry chloroform as solvent gives (ptolyl)(3)PC(COMe)(COC(6)H(5)), alpha-acetyl-alpha-benzoylmethylenetriphenylphosphorane (1), {(p-tolyl)(3)PC(COMe)(COC(6)H(4)NO(2))} (2), {Ph(3)PC(COMe)(COC(6)H(4)NO(2))} (3), {Ph(3)PC(COMe)(COC(6)H(4)OCH(3))} (4), {(p-tolyl)(3)PC(COCH(3))(2)} (5), and {Ph(3)PC(COMe)(COOCH(2)C(6)H(5))} (6). Single crystal X-ray analyses for ylides 2, 5, and 6 reveal the monoclinic (2, 5) and triclinic (6) crystal systems. Characterization of the obtained compounds was also performed by elemental analysis, IR, (1)H, (31)P, and (13)C NMR. The geometries of these compounds have been investigated using density functional theory (DFT). In addition, electronic parameters of these compounds such as HOMO and LUMO energy, Mulliken partial charge, and dipole moment were obtained. In this paper, the reactivity of these ylides is discussed in regard to the aforementioned data