Skeletal Analogues of UCS1025A and B by Cyclization of Maleimides: Synthesis and Biological Activity

Abstract

Application of a direct ring-closing approach which exploits an intramolecular aldol reaction with a ketene silyl acetal onto a remote imide function leading to the core skeleton of UCS1025A and B effectively provides access to small library of substituted analogues; of interest is their complete lack of antibacterial activity against MRSA (Gram+) and E. coli (Gram–) bacterial strains.

Total Synthesis of UCS1025A via Tandem Carbonylative Stille Cross Coupling and Diels‐Alder Reaction†

“…[ [1][2][3][10][11][12][13][14][15][16][17] Several elegant total syntheses of UCS1025A (1) have been reported (Figure 1B). In 2005, Danishefsky and Lambert completed the first asymmetric total synthesis of UCS1025A in 11 steps (the longest linear sequence, LLS).…”

“…The complex structures and remarkable biological activities of the pyrrolizidinone polyketides have attracted significant synthetic attention. [ 1‐3,10‐17 ] Several elegant total syntheses of UCS1025A ( 1 ) have been reported (Figure 1B). In 2005, Danishefsky and Lambert completed the first asymmetric total synthesis of UCS1025A in 11 steps (the longest linear sequence, LLS).…”