C. P. Smith

Reaction of trialkyl phosphites with aromatic aldehydes: Carboncarbon condensations from the reaction ofp-nitrobenzaldehyde and ofo-nitrobenzaldehyde with trialkyl phosphites—new routes to glycol phosphates

Abstract Trialkyl phosphites induced a carbon carbon condensation reaction in p -nitrobenzaldehyde and in o -nitrobenzaldehyde, at 20°. The products were 2,2,2- trialkoxy -4,5- di nitrophenyl )1,3,2- dioxaphospholanes . Both diastereomers at carbon were produced; the major isomer had the meso -configuration. The phospholanes were hydrolyzed to glycol phosphotriesters of known configuration. The phospholanes were converted into dinitrostilbene oxides of known configuration by hot alcohol. m -Nitrobenzaldehyde, the chlorobenzaldehydes, and aromatic aldehydes with electron-releasing groups, failed to react with trialkyl phosphites at 20°. A previous report of the course of these reactions was shown to be in error.

Nucleophilic 1,2-additions to the carbonyl group of p-quinones : Hydrolysis and alcoholysis of the pentaoxyphosphoranes derived from the condensation of α-diketones with p-quinones by means of trialkyl phosphites

Abstract The tendency of certain nucleophiles to perform 1,2-additions to the CO group of p-quinones has been demonstrated. The nucleophile was 2,2,2-trimethoxy—4,5-dimethyl-2,2-dihydro-1,3,2-dioxaphospholene, made from biacetyl and trimethyl phosphite. The products of the 1,2-additions to p-benzoquinone and to 1,4-naphthoquinone were derivatives of the 2,2-dihydro-1,3,2-dioxaphospholane ring system with pentacovalent phosphorus. These pentaoxyphosphoranes were converted by one equivalent of water into biacetyl, methanol and the phosphate ester of the corresponding hydroquinone. Methanol induced a molecular rearrangement of the pentaoxyphosphoranes; the products were methyl acetate, trimethyl phosphate and the p-acetyl-phenols, i.e. acetophenone and 1-hydroxy-4-acetyl-naphthalene, respectively.

Trialkyl phosphites as reagents in the carbon-carbon condensations of α-diketones with α,β-unsaturated aldehydes : The hydrolyses of 5-membered cyclic pentaoxyphosphoranes and phosphate esters

Abstract 2,2,2-Trimethoxy-4,5-dimethyl-2,2-dihydro-1,3,2-dioxaphospholene, made from trimethyl phosphite and biacetyl, reacted with crotonaldehyde and gave 2,2,2-trimethoxy-4β-methyl-4α-acetyl-5α-( trans -1-propenyl) 2,2-dihydro-1,3,2-dioxaphospholane. The hydrolyses of the phospholane by one mole equivalent of water in aprotic solvents and by an excess of water were studied. Two hydrolytic pathways were observed at 20°. (1) A substitution of the OMe groups on phosphorus by OH groups. This led to 5-methyl-2-heptene-4,5-diol-6-one-(5-dihydrogen phosphate), which underwent a relatively slow isomerization to the corresponding 4-dihydrogen phosphate. (2) An attack by water on the allylic carbon, with CO bond fission. This led to the formation of trimethyl phosphate and 5-methyl-2-heptene-4,5-diol-6-one. At 100°, the dihydrogen phosphate ester lost phosphoric acid and gave an unsaturated dihydroxy-ketone. Methanolysis of the phospholane produced trimethyl phosphate and 4-methoxy-5-methyl-2-heptene-5-ol-6-one byCO bond fission.