Structural analysis of three methyl N-phosphorylated 5,6-dihydroxy-2-azabicyclo[2.2.1]heptane-3-carboxylates
摘要:
Both exo and endo isomers of (+/-)-methyl N-diphenylphosphoryl-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate and (+/-)-methyl N-diphenylphosphoryloxy-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate were dihydroxylated with OsO4. The unexpected formation of (+/-)-methyl 5,6-dihydroxy-N-diphenylphosphoryl-2-azabicyclo[2.2.1]heptane-3-endo-carboxylate from (+/-)-methyl N-diphenylphosphoryloxy-2-azabicyclo[2.2.1]hept-5-ene-3-endo-carboxylate is discussed based on NMR analyses and experimental observations. The two N-diphenylphosphoryl dihydroxybicycles are analyzed in terms of their crystalline structure by X-ray crystallography. (C) 2011 Elsevier B.V. All rights reserved.