Enantioselective total synthesis and assignment of the absolute configuration of (+)-laurokamurene B

The first enantioselective total synthesis of the rearranged aromatic sesquiterpene (+)-laurokamurene B, isolated from the Chinese red algae Laurencia okamurai Yamada, has been accomplished starting from (S)-campholenaldehyde, establishing the absolute configuration of laurokamurenes.

Figure optionsDownload as PowerPoint slide

Methyl 2-[(1S,3S)-2,2,3-trimethylcyclopent-1-yl]acetateC11H20O2[α]D23=-9.0 (c 3.8, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1S,3S)

Methyl 2-[(3S)-2,2,3-trimethylcyclopent-1-ylidene]acetateC11H28O2[α]D24=-7.5 (c 4.6, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (3S)

(1R,3S)1-[4-Methylphenyl]-2,2,3-trimethylcyclopentan-1-olC15H22O[α]D23=+10.7 (c 1.4, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,3S)