Chemoenzymatic Synthesis and Synthetic Application of Enantiopure Aminocyclopentenols: Total Synthesis of Carbocyclic (+)-Uracil Polyoxin C and Its α-Epimer

Abstract

Carbocyclic uracil polyoxin C (+)-2 and its alpha-epimer (-)-3 were synthesized in an efficient fashion from cis-4-(N-tert-butylcarbamoyl)cyclopent-2-en-1-ol (+/-)-7. The synthesis incorporates a concise, inexpensive chemoenzymatic synthesis of enantiopure aminocyclopentenols, a Pd(0)-catalyzed substitution reaction, and a mild reduction of an alpha-nitro ester by TiCl(3)/sodium borohydride. Significantly, this process demonstrates the synthetic utility of the versatile enantiopure aminocyclopentenol building block (-)-4.