Nucleophilic transformations of cyclic phosphate triesters

• Published in: Tetrahedron letters Vol. 45; no. 43; pp. 8003 - 8006
• Main Authors: Ashkenazi, Nissan, Karton, Yishai, Segall, Yoffi
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 18.10.2004; Elsevier
• Subjects: Chemistry; Chemistry, Organic; Cyclic phosphate triesters; Grignard reagents; Nucleophilic attacks; Phosphites; Phosphonates; Physical Sciences; Science & Technology; Grignard reagents; Phosphites; Nucleophilic attacks; Cyclic phosphate triesters; Phosphonates; PHOSPHORUS; CARBON; CATALYZED HYDROPHOSPHORYLATION; HYDROLYSIS; phosphites; REGIOSELECTIVITY; ESTERS; nucleophilic attacks; CHEMISTRY; cyclic phosphate triesters; phosphonates; ORGANOPHOSPHORUS COMPOUNDS; GRIGNARD-REAGENTS
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2004.09.011

[Display omitted] Reactions of cyclic phosphate triesters, such as 2-ethoxy-1,3,2-dioxaphospholane 2-oxide, with Grignard reagents such as phenyl-, alkyl-, ethynyl-, and allyl-magnesium halides result in ring opening leading to the corresponding phosphonates, via nucleophilic attack of carbon on the phosphorus atom. Treatment of 2-ethoxy-1,3,2-dioxaphospholane 2-oxide with sodium borohydride yields ethyl 2-hydroxyethyl phosphite. This reaction is exclusive for the five-membered cyclic system: under these conditions acyclic phosphate triesters, such as triethyl phosphate, are unreactive and the analogous six-membered ring system, 2-ethoxy-1,3,2-dioxaphosphorinane 2-oxide reacts only partially to give unidentified phosphate esters and traces of phosphonate products. Both compounds were inert to NaBH 4.