Conformationally constrained alpha-boc-aminophosphonates via transition metal-catalyzed/curtius rearrangement strategies.
A transition metal-catalyzed/Curtius rearrangement sequence toward the development of conformationally constrained alpha-Boc-aminophosphonates 2-6 is described. An approach using the versatile tert-butylphosphonoacetate moieties 1a and 1b to derive an array of mono- and bicyclic alpha-Boc-aminophosphonate systems is presented. Conformational constraint is incorporated using either the ring-closing metathesis reaction catalyzed by the first generation Grubbs catalyst or intramolecular cyclopropanation mediated by Rh2(OAc)4. Using the tert-butyl ester functionality in 1a or 1b as a potential amino group, the Curtius rearrangement provides an efficient route toward the target alpha-Boc-aminophosphonates.
Moore
Joel D
JD
Department of Chemistry, University of Kansas, Lawrence, Kansas 66045-7582, USA.
Sprott
Kevin T
KT
Hanson
Paul R
PR
D000588:Amines / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D008968:Molecular Conformation; D063065:Organophosphonates / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D028561:Transition Elements
D000588:Amines; D063065:Organophosphonates; D028561:Transition Elements