Synthesis and Nuclear Magnetic Resonance Spectroscopy of some Substituted Aryldiazoalkanephosphonates

Abstract

Six aryl diazoalkanephosphonates have been prepared and their proton and I3C n.m.r. spectra analyzed. The results suggest that the carbon bearing phosphorus (and the diazo-group) is essentially sp2 hybridized and that the dominant canonical form depends on the substitution of the aryl ring. Evidence is given for double bond character in the C-P bond.Six diazoalcanephosphonates d'aryle ont ete prepares et leurs spectres en r.m.n. du proton et du I3C ont ete analyses. Les rtsultats suggerent que le carbone porteur du groupe phosphore (et du groupe diazo) possede exclusivement une structure sp' hybridee et que la forme canonique dominante depend de la substitution sur le cycle aryle. Le caractere de double liaison dans le lien C-P a aussi Cte mis en evidence.[Traduit par le journal]Can.

Assignment of Configuration of Dehydrochlorination Products of Mitotane

“…The effect of the position of substitution on an aromatic ring and the resulting influence on the NMR of adjacent vinylic protons are shown by an examination of data obtained by Gurudata et al on some aryl substituted styrenes (10). An examination of the chemical shift for the a-proton (Structure 111, C) in the o-chloro-substituted derivative compared to the p-chloro compound shows that this proton is deshielded 0.45 p.p.m.…”

λ5-Phosphorus-Containing α-Diazo Compounds: A Valuable Tool for Accessing Phosphorus-Functionalized Molecules

“…Following an analogous protocol, Gurudata et al prepared a large series of dimethyl α-aryl-, α-alkyl-, α-cycloalkyl-, and α-vinyl-α-diazomethylphosphonates. , …”

“…30,38 Following an analogous protocol, Gurudata et al prepared a large series of dimethyl α-aryl-, α-alkyl-, α-cycloalkyl-, and αvinyl-α-diazomethylphosphonates. 39,40 The alkaline cleavage of the p-toluenesulfonylhydrazones 12a,b allowed them to get the corresponding conjugated 1,3diene unit-containing α-diazomethylphosphonates 13a,b (Scheme 5). 41 By Bamford−Stevens-type elimination, α-diazomethylphoshinic esters 14 were also prepared (Figure 2).…”

“…219 It is noteworthy that the configuration of the formed pyrazolines was determined by a detailed analysis of the 1 H NMR spectra taking advantage from the reported vicinal 31 P−C−C− 1 H coupling constants 220 and the stereospecific vicinal homoallylic 5 J PH coupling constants. 221 Up to the present, Benezra's papers 11,26,39,218 still remain of substantial value in the poor scenario of spectroscopic data on phosphoruscontaining compounds.…”