A Crystalline Tetraalkoxyalkylphosphorane from the Reaction of Trimethyl Phosphite with an α,β-Unsaturated Ketone. 3-Benzylidene-2,4-pentanedione. P³¹ and H¹ Nuclear Magnetic Resonance Spectra^1,2

The behavior of 2-substituted-1,3-diphenylpropane-1,3-tione toward organophosphorus reagents

“…Experimental section). The formation of compounds 5a-c involves Michael addition [16,17] [18]. The latter collapses to give the dialkyl phosphonate products 5a-c (Scheme 3).…”

Reactions of phosphite esters and trisdialkylaminophosphines with 5‐substituted 1,3,4‐thiadiazol derivatives

“…Addition of water (unavoidable moisture) to each dipolar ion, structure (A), produces a transient intermediate (B) with pentacovalent phosphorus [16]. The latter collapses to give the respective dialkyl phosphonate products (4a-c) (Scheme 2).…”

“…We have found that the reaction of trisdimethylaminophosphine (3a) with 1a proceeds in boiling toluene to give chromatographically the pure adduct 6a assigned the open dipolar structure based on the following evidence: (i) elemental analyses and a molecular weight determination (MS) for compound 6a support the molecular formula C 16 [19].…”

The reactions of Wittig-Horner reagents with 1,3-dioxo-?2,?-indanmalononitrile

“…(c) Adduct 3 possesses the phosphonate structure since it exhibits a positive shift in its 31 P NMR spectrum (d ‫ס‬ ‫7.02ם‬ vs. 85% H 3 PO 4 ) and absorbs in the region characteristic for this class of compounds [5][6][7]. The 1 H NMR spectrum of compound 3 shows signals at d ‫ס‬ 1.14 (6H, P-OCH 2 CH 3 , t), 4.05 (4H, P-OCH 2 CH 3 , m), 3.2 (1H, d, with J HP ‫ס‬ 10 Hz), and 8.32 (1H, exchangeable with D 2 O, ‫מ‬OH proton, s).…”