Rapid method of preparation of phospholanium perchlorates via intramolecular cyclizations of 4-hydroxybutylorganophosphines

Abstract

A rapid synthetic procedure for the preparation of phospholanium perchlorates in high yield has been developed. The process involves the cleavage of tetrahydrofuran by lithium organophosphides, affording 4-hydroxybutylorganophosphines, which are then intramolecularly cyclized in an aqueous solution. The following phospholanium salts (very tediously prepared by other methods) have been obtained by this procedure: methylphenyl-, ethylphenyl-, n-propylphenyl-, n-butylphenyl-, and diphenylphospholanium perchlorate. Evidence is also presented to show that cleavage of THE by diethylphenylphosphine and lithium metal afforded not only the expected diethyl-4-hydroxybutylphosphine, but also ethyl-4-hydroxybutylphenylphosphine. Confirmation of this was obtained in the form of subsequent intramolecular cyclization of these phosphines to the corresponding diethylphospholanium perchlorate and ethylphenylphospholanium perchlorate. Extension of this synthetic procedure to tetrahydropyran also afforded the desired phosphorinanium perchlorate in good yield.

Reactions of Cyclopalladated Complexes with Lithium Diphenylphosphide

“…In a year, Mallion and Mann described the preparation of Ph 2 P(CH 2 ) 4 OH in 22% yield by heating a 1:1 mixture of Ph 2 PH and BuLi in THF for 7 h . Similar results have also been disclosed by other groups, although heating time and yields of Ph 2 P(CH 2 ) 4 OH vary. , …”

“…33 In a year, Mallion and Mann described the preparation of Ph 2 P-(CH 2 ) 4 OH in 22% yield by heating a 1:1 mixture of Ph 2 PH and BuLi in THF for 7 h. 34 Similar results have also been disclosed by other groups, although heating time and yields of Ph 2 P(CH 2 ) 4 OH vary. 35,36 The LiPPh 2 solutions in THF purchased from Sigma-Aldrich Co. were checked for the presence of Ph 2 P-(CH 2 ) 4 OLi before reacting with a CPC. According to the 31 P{ 1 H} NMR data for the original LiPPh 2 solutions and the 1 H NMR data for the crude product obtained after quenching these solutions with H 2 O, the reagents did not have even traces of Ph 2 P(CH 2 ) 4 OLi.…”

Phosphine–phosphite ligands: chelate ring size vs. activity and enantioselectivity relationships in asymmetric hydrogenation

“…THF) by LiPPh 2 and the subsequent hydrolysis of the Li-alcoholate (n = 4). 12 Then these valuable intermediate hydroxyphosphines can be combined with chlorophosphites a Department of Organic Chemistry, University of Pannonia, H-8200 Veszprém, Egyetem u. 10, Hungary.…”