The Total Synthesis of (±)‐Isopisiferin Methyl Ether

Abstract

A novel and effective convergent synthesis of (=)-isopisiferin methyl ether, a rearranged abietane diterpene, having a hexahydrodibento [a,o'] cycloheptene ring system, was achieved by Wittig reaction, selective hydrogenation and selective oxidation. INTRODUCTIONThe rearranged 9(10+2O)-abeo-8,11,13-triene diterpenoids, the rare structural type of diterpene thought to arise from the rearrangement of the more familiar abictane skeletone', have received considerable attention in the last few years. Several new members of this group have been described* such as isopisiferin(l), barbatusol(3), xochitloldione(5), and the total syntheses some of them have been reported3. As a part of our synthetic studies on the naturally-occuring diterpenes, we have attempted to synthesize this rare structural type of diterpene. On the basis of a successful synthesis of barbatusol methyl ether, we have studied the total synthesis of (+)-isopisiferin methyl ether(2),

Enantioselective Synthesis and Olfactory Evaluation of Bicyclic α- and γ-Ionone Derivatives: The 3D Arrangement of Key Molecular Features Relevant to the Violet Odor of Ionones

“…On the basis of our original retrosynthetic strategy (Scheme ), at first we concentrated our efforts toward the direct allylic oxidation of O -TBDPS-protected α-cyclogeraniol 14a to aldehyde 19 . Although this transformation had been already described in the literature for a related substrate, we were unable to reproduce this procedure for a clean oxidation of 10a , obtaining, instead, a complex mixture of products. Therefore, we resorted to a more tortuous route in order to functionalize the C-10 position of compound 10 .…”

Structure, biosynthetic relationships and chemical synthesis of the icetexane diterpenoids

“…70 A concise synthesis of (AE)-isopisiferin methyl ether was reported by Pan and co-workers in 1995 (Scheme 7). 71 Majetich and co-workers used a cyclialkylation 72 reaction in their total synthesis of (AE)-pisiferin in 1996 (Scheme 8). 73 This strategy was first employed in natural product synthesis by Majetich et al in the total synthesis of (AE)-barbatusol (vide infra, Scheme 11).…”

“…77 The strategy employed was similar to that used by the same group for the synthesis of (AE)-isopisiferin methyl ether (see Scheme 7). 71 Pan and co-workers followed their synthesis of barbatusol methyl ether with the first total synthesis of (AE)-demethylsalvicanol in 1996 by (Scheme 13). 78 The synthesis began with lithiation of veratrole (116) and trapping of the resulting anion with ethyl chloroformate to give an ester that was regioselectively brominated to yield bromide 117.…”

Total Synthesis of (–)‐Isopisiferin: Confirmation of Absolute Configuration

“…[6][7][8] Herein, we wish to present the first enantioselective synthesis of natural 1 in a simple and convergent route.…”