Reactivity of cyclic sulfamidates towards phosphonate-stabilised enolates: synthesis and applications of alpha-phosphono lactams.
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.
Bower
John F
JF
School of Chemistry, University of Bristol, Bristol, UK BS8 1TS.
Williams
Andrew J
AJ
Woodward
Hannah L
HL
Szeto
Peter
P
Lawrence
Ron M
RM
Gallagher
Timothy
T
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*
D007659:Ketones; D007769:Lactams; D063065:Organophosphonates; D013449:Sulfonamides