.alpha.-Bromo-.alpha.-ketol phosphates and enediol bis-phosphates

Reactions of α-Diketones ando-Quinones with Phosphorus Compounds

“…156 When the above reaction takes place in acetic anhydride at room temperature, the fumarates 207, maleates 208, benzofuran derivatives 209 (R 1 ) H, R 2 ) CPh 3 ; R 1 ) CPh 3 , R 2 ) H), and diacetoxy compound 210 are formed. 79 Reaction of o-naphthoquinone (211) with ethoxycarbonylmethylene(triphenyl)phosphorane (152, R ) Et) and/or its methyl analogue (152, R ) Me) gives, beside the coumarin derivatives 212 previously reported, 152 the γ-lactones 213. 153 When acetic anhydride is used as a solvent in the above reaction, diethyl (1-acetoxy-2-naphthyl)maleate ( 214) and the coumarin derivative 212 are obtained.…”

“…However, on heating they regenerate the starting materials , with dry oxygen, ,, and with a variety of reagents, such as bromine , and ozone. ,, …”

“…However, on heating they regenerate the starting materials. 208 They react very rapidly with water, 19,209 with dry oxygen, 191,193,210 and with a variety of reagents, such as bromine 191,211 and ozone. 191,212,213 The nucleophilic additions of 1,3,2-dioxaphospholenes 315 to a large variety of R-dicarbonyl compounds give rise to new families of oxyphosphoranes.…”

Displacement Reactions of Phosphorus(V) Compounds and Their Pentacoordinate Intermediates

“…of water in ether solution at O°C[61el. Reaction 6.7[61b+1 f H 3 7 [' H,O f "' T 7' Diastereomeric live-membered cyclophosphotriesters such as (21) and (22), Reaction 6.8, which differ by the configuration at the phosphorus, undergo rapid diastereomerization by inversion at the P-center under the catalytic influence of methanolrgb1. Permutational isomerization of the hypothetical oxyphosphorane intermediates by the TR with the ring as the pair accounts for these observations.…”

“…Reactions 3.6,3.7,3.8,and 3.9 are reported examples in which phosphonium compounds and phosphane oxides containing small rings undergo displacements and reductions, respectively, with retention of the phosphorus configuration. (In Reaction 3.7, the displacement is (21) (TR)3 processes tend to have higher barriers than the single TR process. The TR which uses the ring as the pair and which moves the leaving group X to an apical position is denoted by the permutation (1 2)@ Y 3) and transforms TBP (12) into (13).…”