Studies Directed Toward the Total Synthesis of 14-Membered Cyclopeptide Alkaloids: Synthesis of a Linear Precursor to Nummularine-F

Abstract

Investigations leading to the synthesis of a linear precursor (2) to the 14-membered cyclopeptide alkaloid, nummularine-F, are described. The Ugi four-component condensation reaction was utilized to prepare the key intermediate (3) which, under mild conditions, was elaborated to 2. The attempted cyclization conditions all led to the formation of a 28-membered cyclopeptide.