- The first examples of enantiomerically pure diphosphane dioxides-(R(P),R(P))- and (S(P),S(P))-1,2-di-tert-butyl-1,2-diphenyldiphosphane 1,2-dioxides, and (R(P))- and (Sp)-1-tert-butyl-1,2,2-triphenyldiphosphane 1,2-dioxides
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Whereas oxidative dimerization of each of the lithiated reagents (R(P))- and (S(P))-tert-butylphenylphosphane oxides 1 Li and 2 Li by means of oxygen in THF at low temperature led cleanly to meso-1,2-di-tert-butyl-1,2-diphenyldiphosphane dioxide (3), the respective nucleophilic substitution reactions of 1 Li and 2 Li with the (R(P))- and (S(P))-tert-butylphenylphosphinic bromides (4 and 6) in THF under argon led to the corresponding (S(P),S(P))-and (R(P),R(P))-1,2-di-tert-butyl-1,2-diphenyldiphosphane dioxides (5 and 7) in good yields together with the meso-diphosphane dioxide 3. The structures of 3 and 5 were established by X-ray crystallography. Similarly, the reaction of lithiated (R(P))-phosphane oxide 1 Li with diphenylphosphinic bromide (8) or of achiral lithiated diphenylphosphane oxide 10 Li with (R(P))-tert-butylphenylphosphinic bromide (4) provided (S(P))-tert-butyltriphenyldiphosphane dioxide (9).
- Haynes, Richard K.,Lam, William Wai-Lun,Williams, Ian D.,Yeung, Lam-Lung
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- Preparation of new imidazol-2-yl-(amino)methylphosphonates, phosphinates and phosphine oxides and their unexpected cleavage under acidic conditions
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The efficient synthesis of new imidazol-2-yl-(amino)methylphosphonic acids, phosphonates phosphinate esters and phosphine oxides is described. The synthetic methodology is based on nucleophilic addition of phosphorus species to imidazole-2 derived imines.
- Boduszek, Bogdan,Olszewski, Tomasz K.,Goldeman, Waldemar,Grzegolec, Kamila,Blazejewska, Patrycja
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p. 1223 - 1229
(2012/02/16)
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- New quinoline-2, -3, and 4-yl-(amino) methylphosphonates: Synthesis and study on the C-P bond cleavage in quinoline-2 and -4 derivatives under acidic conditions
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Synthesis of new quinoline-(amino)methylphosphonic acids, their phosphonate esters, and phosphine oxides is presented. The desired new compounds were efficiently obtained by nucleophilic addition of phosphorous species to quinoline-derived Schiff bases. In addition, it was discovered that heating of quinolin-2 and quinolin-4-yl-(amino)-methylphosphonates with aqueous HCl leads to their decomposition resulting in a rupture of the C-P bond, rejecting of the phosphorus containing fragment, and formation of the corresponding secondary quinoline-2 and quinoline-4-alkylamines. Two alternative mechanistic pathways for this cleavage are postulated. Copyright
- Michalska, Joanna,Boduszek, Bogdan,Olszewski, Tomasz K.
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p. 617 - 624
(2011/12/04)
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- Studies on the interaction of phosphine selenides and their structural analogues wth dihalogens and sulfuryl chloride
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The phosphine selenides, tris(dimethylamino)phosphine selenide, esters of selenophosphoric acid, and esters of selenophosphonic acid react with dihalogens and sulfuryl chloride to form halogenoselenophosphonium salts (≡ 3P-SeX)+X-. T
- Krawczyk, Ewa,Skowronska, Aleksandra,Michalski, Jan
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p. 4471 - 4478
(2007/10/03)
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- Phosphinoyl radicals: Structure and reactivity. A laser flash photolysis and time-resolved ESR investigation
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The photochemistry of a series of bis(acyl)phosphine oxides and the rate constants of the reactions of their phosphorus radicals with n-butylacrylate, thiophenol, bromotrichloromethane, oxygen, and methyl viologen have been investigated by laser flash pho
- Jockusch, Steffen,Turro, Nicholas J.
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p. 11773 - 11777
(2007/10/03)
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- Preparation of 3-substituted cephalosporins
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There is described a process for preparing an enamine of formula (IX): STR1 where R2 is a carboxylic acid protecting group and R3 is the residue of a carboxylic acid derived acyl group and where R5 and R6 are the same or different C1-4 alkyl or C7-10 aralkyl groups; or taken together with the adjacent nitrogen atom form a heterocyclic ring containing from 4 to 8 carbon atoms and optionally a further heteroatom selected from oxygen and nitrogen; by reacting a compound of formula (XII): STR2 with an amine of formula HNR5 R6, the reactant of formula (XII) being prepared by reaction of an appropriate enol derivative with a phosphorus reagent. The enamines of formula (IX) are useful in the preparation of 3-hydroxycephalosporins.
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