Phosphite, difluoro-, methyl

A synthesis of racemic fmoc-protected 4-phosphonomethylphenylalanine starts with the Arbuzov preparation of (257) (R = Me or Bu ) standard modifications to the aryl methyl group lead to the desired (258). Two procedures have been adopted for the preparation of the N-ivaoc or iV-boc derivatives of the difluoro derivative (259). In the first, triethyl phosphite and 4-(bromomethyl)benzoyl bromide and treatment of the resultant aroyl phosphonate with the DAST reagent yields (262) this reacts with the carbanion from (263) to give (264) hydrogenation of which (with PdCla) affords (260), then converted into its N-fmoc derivative and de-esterified with MeaSil. In the second procedure, triethyl phosphite and 4-iodobenzoyl chloride, followed by DAST reagent, yielded diethyl [difluoro(4-iodophenyl)methyl]phosphonate which was caused to react... 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ ]

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