A Synthetic Study in the Tricyclovetivene Series

Abstract

The total synthesis of racemic tricyclovetivene ( l a ) and isomers ( l b and 26) is described. The crucial reaction of the synthesis is a cyclization (iii) developed in this laboratory.La synthtse totale du tricyclovetiv6ne ( l a ) racemique et de ses isomtres ( l b et 26) est dkcrite. L'etape cruciale de la synthtse est une cyclisation (iii) mise au point dans ce laboratoire.

Chemoenzymatic total synthesis ofent-neopinone and formal total synthesis ofent-codeinone from β-bromoethylbenzene*

“…2 came from Wiesner's zizanoic acid synthesis published in 1972. 28 In one of his many ingenious solutions to the synthetic problems of that particular era, he conceived the construction of tricyclic enone 12, the key intermediate in his synthesis of zizanoic acids, from the b,g-deconjugated enone 10 under both acid-and base-catalyzed conditions, as shown in Fig. 3 in an abbreviated manner.…”

“…3) with C-9 and C-14 of the morphine skeleton, we saw the opportunity to explore the reactive options of intermediates such as 7 and 8, whose functional disposition closely resembles the compounds used by Wiesner. 28 The synthesis of the key protected aldehyde 6 required the connection of ring A and ring C fragments via Mitsunobu reaction, followed by Heck cyclization, to establish the C-13 stereogenic center. The synthesis of both fragments, adopted from our previous synthesis of codeine and its enantiomer, proceeded at medium scale as shown in Scheme 1 and was subjected to a moderate degree of optimization.…”

“…, 272(20), 258 (34), 231(29), 230 (72), 215 (40), 167 (30), 150(26), 149 (100), 112(21), 83(28), 71 (36), 70 (84), 69(20), 57 (52), 55(26), 44 (41), 43 (49), 41 (31); HRMS-EI (m/z): M + calcd. for C 17 H 19 NO 4 : 301.1314, found 301.1310.…”

Synthetic photochemistry. A new synthesis of (±)-zizaene via an intramolecular variant of the de Mayo reaction

“…This approach was based on fragmentation of a tricyclo[3.2.1 .03y6]octane carbon framework, i.e. (3) or (4), produced by intramolecular [2 + 21 photocycloaddition of an enol acetate, i.e. (2), derived from a 4-prop-2-enylcyclopentane-1,3-dione (see Scheme 1): In this paper we describe the application of this synthetic design to a new synthesis of the tricyclic ketone (37) which is a central intermediate in Coates' synthesis of z i ~a e n e .…”