Total synthesis of racemic 2-desoxystemodinone and stemodinol; the identity of natural "stemodinol" with stemarin

Abstract

Total syntheses of the naturally occurring diterpenoid 2-desoxystemodinone (3) and the diterpenoid structure 2 ("stemodinol") are described. The synthetic diterpenoid 2 was not identical to an authentic sample of "stemodinol". The authentic sample was found to be stemarin to which structure 2 had been erroneously assigned in the literature. It would appear that the diterpenoid represented by 2 has not been isolated from natural sources.

Stemodane Diterpenes and Diterpenoids: Isolation, Structure Elucidation, Biogenesis, Biosynthesis, Biological Activity, Biotransformations, Metabolites and Derivatives Biological Activity, Rearrangements

“…The same group then addressed the structure elucidation work of what was supposed to be (+)-stemodinol (4). The investigation on this new diterpenoid (m.p.…”

Construction of Tricyclic Enone, a Common Precursor for Aphidicolane and Stemodane B/C/D-Ring System

“…The fusion of the five-membered C ring to B in stemodanes 1 and 2 is cis in contrast to the trans fusion in aphidicolin 3. Aphidicolin is known as a potent antitumor (inhibits DNA replication and growth of several human and neoplastic cells) [10][11][12] and antiviral agent (promising activity against Herpes simplex).13-15) Stemodanes, with a similar structure to aphidicolanes, is expected to have related pharmacological activities.Their important medicinal properties as well as the presence of more than six stereocenters and four quaternary carbons, especially the two adjacent quaternary carbons at C-9 and C-10, make these natural products a worthy synthetic challenge.16) Although there are several reports on the synthesis of stemodinone, [17][18][19][20] other stemodanes, [21][22][23][24][25][26][27][28][29][30][31][32][33] and aphidicolanes [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] in a racemic form, asymmetric synthesis of this class of compounds is relatively rare.54-58) The asymmetric total synthesis of aphidicolin was first achieved by Holton and co-workers in 1987. 54) After that, formal synthesis of (ϩ)-aphidicolin was reported by Tanis 55) an...…”

“…1). [2][3][4][5][6][7] Aphidicolin (3), 8,9) which has a highly related tetracyclic ring system to stemodanes 1 and 2, was isolated from Cephalalosporium aphidicola by Hesp and co-workers and later found to occur in Nigrosporum sphaerica. The fusion of the five-membered C ring to B in stemodanes 1 and 2 is cis in contrast to the trans fusion in aphidicolin 3.…”

A Stereoselective Total Synthesis of (±)‐Maritimol, (±)‐2‐Deoxystemodinone, (±)‐Stemodinone, and (±)‐Stemodin

“…A delphinine-type rearrangement was on the contrary used for the syntheses of 2b [14], 3 [15],and2d [16].…”

“…RO J$J 10a R = H , R'= OCH2CH20, R " = H , H 11 R=CH*Ph, R'=O, R = H , H 12 R = H, R'= 0, R"= H, H 13 R = CHZPh, R = 0, R"= CHOH Alcohol 10a was then protected as benzyl ether by refluxing it in THF with benzyl bromide in the presence of NaH; after standard workup, treatment with dilute HC1-solution unblocked the keto group giving directly compound 1 14).…”