Revision of the Structure and Total Synthesis of Altenuisol

Abstract

Abstract A total synthesis of the reported structure of altenuisol is described. Comparison of the 1 H NMR spectra of the synthesized compound and of the natural product revealed that the originally proposed structure was not correct. Consequently, two constitutional isomers were synthesized. The spectra of one of these compounds – a structure originally proposed as the structure of altertenuol – matched perfectly with the spectra of the natural product. The total synthesis of altenuisol was thus achieved starting with phloroglucinic acid and protocatechuic aldehyde in 10 steps and in 23 % yield, where the longest linear sequence consisted of 6 steps. The key step was a Suzuki coupling with concomitant formation of the lactone ring. Whether altertenuol is identical with altenuisol could not be decided.