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P/O ligand systems: Synthesis and reactivity of primary and secondary o-phosphinophenols by Joachim Heinicke; Ulrich Jux; Renat Kadyrov; Mengzhen He is a Chemistry article available to read on EtoBox.

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Several organometallic reagents such as lithium 2lithio 4-methylphenolate 1 intermediates formed by orthometallation of o-bromoaryloxy-phosphorus(V)-2 or -phosphorus(III)-derivatives 3 with magnesium and sodium, respectively, as well as O-methoxymethylprotected o-lithio-4-methylphenol 4 were used to synthesize suitable precursors 5,6,9,10 of primary and secondary o-phosphinophenols. The P-C bond formation involved coupling with ClPR(NMe 2 ), CIPR(O)(OEt) or an intramolecular carbanionic O → C shift of the P-substituent. Reduction with LiAlH 4 , in the cases of phosphonous or phosphinous acid amides after alcoholysis (to 7,8,11), produced primary and secondary o-phosphinophenols 12, respectively, or Oprotected derivatives 13. o-Phosphinophenols 12 are easily protonated at the phosphorus atom, supported by a P ‫ם‬ -H. . .O hydrogen bridge. Metallation (14), acylation, and silylation (16, take place preferably at the hyxdroxy group and alkylation at the phosphorus atom. Alkylation of 12 and 14 was found to be slow, but C,O-dilithiated species 15 react to give P-secondary (12b,d,e,) or P-tertiary products (20,21). Cyclization of 15a with Me 2 SiCl 2 affords the 2,3-dihydro-1,3,2benzoxa

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Author

Joachim Heinicke; Ulrich Jux; Renat Kadyrov; Mengzhen He

Publisher

John Wiley and Sons; Hindawi Limited; John Wiley & Sons Inc.; Wiley (ISSN 1042-7163)

Published

1997

Language

EN

Field

Chemistry (Physical Sciences)