Proton magnetic resonance and phosphorus-31 nuclear magnetic resonance studies of substituted phospholan-3-one 1-oxides

Abstract

25) Melting points were taken on a Mel-Temp apparatus and are corrected; boiling points are uncorrected. All manipulations of phosphines were conducted in a nitrogen atmosphere in a glove bag. Proton nmr spectra were taken on a Varían A-60 or JEOL MH-100 spectrometer and are referenced to TMS. Proton-decoupled Fourier transform 13C spectra were obtained on a Bruker HFX-10 system at 22.62 MHz utilizing C6Fe In a 3-mm coaxial capillary as external heteronuclear lock; chemical shifts were measured from TMS and then referenced to CS2 using the relation ¿tms = 192.5 ppm. C-P coupling constants are ±1.2 Hz. Proton-decoupled 31P spectra (continuous wave mode) were obtained at 36.43 MHz In a 5-mm tube with C6Fe in a coaxial Insert as lock; offsets relative to prerun 85 % H3PO4 were used to determine values. Elemental analyses were obtained by M-H-W Laboratories, Garden City, Mich. Alkylphosphonous dichlorides used in the synthesis of 1 were commercial samples or were prepared by published methods. (26) G. Grüttner and M.

Polycyclic carbon-phosphorus heterocycles

“…The attempted alkylation of 4-oxo-2-benzyl-2-phosphabicyclo[3.3.0]octane 2-oxide (535) (in enol form) with methyl iodide in the presence of potassium fert-butoxide gave the O-methyl enol ether 536 rather than the expected C-alkylated product. 279 This result was added evidence for the predominance of the enolic form in the starting material.279 A rare example of C-carbonation of a simple C-P heterocycle was reported by Quin.284 The anion derived from 1-methyl-3phospholene oxide (537) by treatment with n-butyllithium at -75 °C underwent carbonation to afford a mixture of acids 538 and 539 in the ratio 2:1 (50%). Although structurally similar polycyclic systems have not been subjected to such a reaction, one would expect similar behavior.…”

Transformation of myrtenoic acid nitrile to aminophospholene oxide by the reaction with dibenzylphosphine oxide: the X-ray structure of (1S,2R,6R,8R)-5-benzyl-9,9-dimethyl-5-oxo-4-phenyl- 5-phosphatricyclo[6.1.1.02,6]dec-3-en-3-ylamine

“…Additionally, tert-butyl methyl ether is immiscible with water and improves the isolation procedure as compared to the traditional procedures. † The mechanism of addition of disubstituted phosphinous acids to unsaturated esters 8 includes the primary addition of phosphinites to the carbon-carbon double bond followed by the addition of a C-anion of the benzylic type to the carbonyl group. The mechanism of the reaction of α,β-unsaturated nitriles seems to be similar, and the addition of the sodium salt of dibenzylphosphine oxide to the carbon-carbon double bond results in primary adduct 2 (Scheme 1), which then undergoes intramolecular cyclisation to form aminophospholene oxide 3.…”

“…The mechanism of the reaction of α,β-unsaturated nitriles seems to be similar, and the addition of the sodium salt of dibenzylphosphine oxide to the carbon-carbon double bond results in primary adduct 2 (Scheme 1), which then undergoes intramolecular cyclisation to form aminophospholene oxide 3. It was shown 8 that in case of the reaction of bulky substrates the use of the second equivalent of a base (to generate a dianion) increased the yields of phospholene oxides. We also used two equivalents of the base because the substrate is sterically hindered.…”

“…According to PM3 calculations, the cis-fusion of a phospholene ring and a pinane moiety is preferable to the transfusion (∆∆H 0 f = 12-15 kcal mol -1 ). In case of the trans-fusion, the vicinal spin-spin coupling constants of P-C(6)-C(2)-C(1) and P-C(6)-C(7)-C (8) in the NMR spectra should be high. However, the experimental values 3 J C-P 0-3 Hz lend support to the cis-fusion.…”

1-Benzy1-2-phenyl-3-hydroxy-4,5-dimethylphosphol-2-ene 1-oxide

“…The title compound represents a novei class of 2-phospholene-3-ole structures which may serve as starting materials for C-P heterocycles with possible biological activity. Certain phospholenes have shown biological activity [Vizel, Zvereva, lvanovskaya, Studentsova, Dunaev & Berim (1965) ;Arbuzav, Vizel, Zvereva, Studentsova & Garaev (1966)] and the fact that alkylation appears to be sterically influenced (Purdum & Berlin, 1974) should stimulate interest. A preliminary report of this structure has been published (Washecheck, van der Helm, Purdum & Berlin, 1975).…”