20148-17-8

2-Hydroxyisophosphindoline-2-oxide 4 and the previously unreported 2-hydroxy-2,3-dihydrophosphaphenalene-2-oxide 5 have been prepared in a one-pot reaction under mild conditions.

Phosphetanic, phospholanic, phosphorinanic, phosphepanic, and phosphocanic acid derivatives have been prepared in a single step by the double Arbuzov reaction of bis(trimethylsiloxy)phosphine (BTSP) with dielectrophiles.Mild, thermal reaction conditions are employed during reaction of BTSP with 1,n-dihaloalkanes (n = 3-7), a ditriflate, and ω-bromo 1,2-epoxides possessing varying levels of steric congestion and functionalization.Isolation and manipulation of pyrophoric BTSP is avoided with in situ generation of the reagent from ammonium hypophosphite and hexamethyldisilazane.Monocyclic, bicyclic, and spirocyclic phosphinic acids are obtained after purification in moderate to good isolated yields.The developed methodology is of particular interest for synthesis of nonhydrolyzable analogues of cyclic phosphodiesters.

The possibilities of synthesizing dialkylphosphinic and cyclic phosphinic acids from ammonium hypophosphite, hexamethyldisilazane, and corresponding halogen derivatives have been studied.These acids can be prepared in low yield, but the simplicity of the process compensates for this disadvantage.

The first phosphines based on the benzo-7-phosphanorbornene system have been prepared and found to have extremely deshielded 31P nuclei.The phosphine with a P-tert-butyl group gives the most downfield value (δ +152.5) ever recorded for a tertiary phosphine.The lone-pair orientation in phosphines controls the magnitude of 2J (PC) and 3J (PC), and these effects were used to determine stereochemical features of the phosphines.These compounds were formed by HSiCl3-pyridine reduction of the Diels-Alder adducts of isophosphindole oxides with norbornadiene. 13C NMR was also used to confirm the assignment of these phosphine oxides.