The enantioselective synthesis of (+)-decipienin A has been carried out. The oxidation of 7-epi-cyperone 2 with molecular oxygen in the presence of methanolic KOH provides de C-6-hydroxylated derivative in quantitative yield. The oxidation of glycols 5a through a Swern oxidation and 14a with TEMPO radical opens up a route to the synthesis of 11-hydroxy sesquiterpenolides. All attempts of oxidation of 5a or 14a with other different oxidation reagents led invariably to fragmentation products. (C) 2001 Elsevier Science Ltd. All rights reserved.
The enantioselective synthesis of (+)-decipienin A has been carried out. The oxidation of 7-epi-cyperone 2 with molecular oxygen in the presence of methanolic KOH provides de C-6-hydroxylated derivative in quantitative yield. The oxidation of glycols 5a through a Swern oxidation and 14a with TEMPO radical opens up a route to the synthesis of 11-hydroxy sesquiterpenolides. All attempts of oxidation of 5a or 14a with other different oxidation reagents led invariably to fragmentation products. (C) 2001 Elsevier Science Ltd. All rights reserved.