[reaction: see text] Asymmetric total syntheses of acid-sensitive (-)-caparrapi oxide (1) and (+)-8-epicaparrapi oxide (2) from farnesol (9) were achieved using Sharpless-Katsuki epoxidation and Lewis acid-assisted chiral Bronsted acid (chiral LBA)-induced polyenecyclization as key steps. Furthermore, (-)-1 could be directly synthesized from (S)-nerolidol (3) and (R)-LBA with 88% ds by reagent control
Biomimetic synthesis of acid-sensitive (−)- and (+)-caparrapi oxides, (−)- and (+)-8-epicaparrapi oxides, and (+)-dysifragin induced by artificial cyclases
Asymmetric total syntheses of acid-sensitive (-)- and (+)-caparrapi oxides (1) and (+)-8-epicaparrapi oxide (2) from farnesol (10) are achieved using Sharpless-Katsuki epoxidation and Lewis acid-assisted chiral Bronsted acid (chiral LBA)-induced polyene cyclization as key steps. The relative configuration of (+)-dysifragin (4) is determined by a single-crystal X-ray diffraction and its totalsynthesis is accomplished