ISSN:
1042-7163
Keywords:
Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Several organometallic reagents such as lithium 2-lithio 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-methoxymethyl-protected 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(NMe2), CIPR(O)(OEt) or an intramolecular carbanionic O → C shift of the P-substituent. Reduction with LiAlH4, in the cases of phosphonous or phosphinous acid amides after alcoholysis (to 7,8,11), produced primary and secondary o-phosphinophenols 12, respectively, or O-protected derivatives 13. o-Phosphinophenols 12 are easily protonated at the phosphorus atom, supported by a P+-H … O hydrogen bridge. Metallation (14), acylation, and silylation (16,17) 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 Me2SiCl2 affords the 2,3-dihydro-1,3,2-benzoxaphosphasilol 22, cyclocondensation of 12c with RP(NMe2)2 or ClP(NMe2)2 furnishes 2,3-dihydro-1,2,3- benzodiphospholes 23 and 24. A phosphiniden-phosphoran 25 is detected in the reaction between 12a and P(NMe2)3. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 383-396, 1997
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
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