A Convenient Synthesis of the Central Core of Helioporins, seco-Pseudopterosins and Pseudopterosins via BCA-Annulation Sequence

Abstract

A convenient synthesis of the central core of helioporins, seco-pseudopterosins and pseudopterosins in racemic form is reported, using a Suzuki coupling (A-ring formation)-Friedel-Crafts acylation sequence, followed by synthetic elaboration of the resulting tetralone derivative. Key steps of the method are a totally diastereoselective cuprate conjugate addition and a final, spontaneous Friedel-Crafts acylation.

Total synthesis of the pseudopterosin aglycones

“…In an attempt to compare syntheses fairly, total step count -reported as longest linear sequence -and yields are measured from commercially available starting materials by incorporating details from these referenced literature procedures. We have elected not to include synthetic studies towards the pseudopterosins that have not yet achieved the final target, [15][16][17][18][19][20][21][22][23][24][25][26][27][28] or the synthesis of simplified analogues [29][30][31][32] (including biosynthetic precursors), [33][34][35][36][37] or the synthesis of the originally proposed structure of the G-J aglycone. 38,39 We begin by presenting biosynthetic considerations, followed by an analysis of structure-goal based approaches (divided into terpene and aromatic starting materials), and we conclude with the recent transform-based strategy.…”