title: Reactivity of cyclic sulfamidates towards phosphonate-stabilised enolates: synthesis and applications of alpha-phosphono lactams.
abstract: Five and six ring a-phosphono lactams 14-20 are available by reaction of 1,2- and 1,3-cyclic sulfamidates respectively with enolates derived from ethyl dialkylphosphonoacetates 3 and 4. Subsequent Wadsworth-Emmons olefination provides the enantiomerically pure exo-alkylidene variants e.g. 25, which is efficiently converted to vinyl triflate 29 (> 98% ee). Suzuki coupling of 29 to a range of aryl and vinyl boronic acids leads to a structurally diverse range of pyrrolidinones exemplified by 30 and 34. The degree of epimerisation at the base-sensitive C(5) stereocentre during the Suzuki coupling of 29 is shown to be dependent on both the nature of the aryl boronic acid and the reaction conditions used.
authors.affiliation: School of Chemistry, University of Bristol, Bristol, UK BS8 1TS.
authors.forename: John F
authors.initials: JF
authors.lastname: Bower
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Williams
authors.forename: Hannah L
authors.initials: HL
authors.lastname: Woodward
authors.forename: Peter
authors.initials: P
authors.lastname: Szeto
authors.forename: Ron M
authors.initials: RM
authors.lastname: Lawrence
authors.forename: Timothy
authors.initials: T
authors.lastname: Gallagher
mesh_terms: D003500:Cyclization; D007659:Ketones / Q000737:chemistry*; D007769:Lactams / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D063065:Organophosphonates / Q000737:chemistry*; D013237:Stereoisomerism; D013449:Sulfonamides / Q000737:chemistry*
chemical_list: D007659:Ketones; D007769:Lactams; D063065:Organophosphonates; D013449:Sulfonamides