A formal total synthesis of (.+-.)-9-isocyanopupukeanane

Tricyclic Sesquiterpenes from Marine Origin

“…The second one (Scheme ) relied on the intramolecular Diels–Alder cyclization of diene olefin 495 (diastereomeric composition not given) synthesized in four steps and 39.2% OY from allylic alcohol 456 , which gave quantitatively the tricyclic ketoalcohols 496 which was transformed in seven more steps to achieve the synthesis of 224 in 17.5% yield. Racemic synthesis of the neopupukeanane derivative 236 based on the same strategy was reported later, and two other racemic syntheses of this pupukeanane-type structure were also described. , …”

“…Racemic synthesis of the neopupukeanane derivative 236 based on the same strategy was reported later, 400 and two other racemic syntheses of this pupukeanane-type structure were also described. 401,402 Only one racemic synthesis of (±)-2-isocyanoallopupukeanane 239 has been reported to date (Scheme 33). 403,404 Lactone 498, prefiguring the final cyclopentane−cyclohexane-bridged skeleton, was obtained in 56% yield via a ring-expansion process, starting from ester 497.…”

The Total Synthesis of (±)‐Camphor and (±)‐Epicamphorenone from Methylcyclopentadiene

“…Hydrogenation of 14 afforded IS, reduction by lithium aluminum hydride of 15 followed by PCC oxidation of the resulting alcohol furnished aldehyde 16. 7 Wolff-Kishner reduction of 16 followed by hydrolysis then afforded (±)-camphor (1),8 of which the IH NMR and infrared spectra, and melting point, were consistent with an authentic sample (Aldrich Company). For the synthesis of (±)-epicamphorenone (2), reaction of the enolate anion of 13 with 5-bromo-2-methyl-2-pentene afforded the diene ester 18 stereoselectively.…”

“…Therefore, the chemistry of MCP and its use in natural product synthesis became challenging target. We describe here the synthesis of (i)-camphor (1) and (i)-epicamphorenone (2) from MCP. 3…”

Marine natural products

“…inhibitor nakafuran-8 (288b), which has been isolated from, D. fragilis,215 D. etheria,216 and several n u d i b r a n ~h s , ~~~, " ' has been synthesized by a route involving two rearrangement steps and a double ring-enlargement.21s ( + )-Euryfuran(289), which is metabolite of a species of Euryspongia 217 and of Dysideu h e r b a ~e a , ~~~ has been synthesized from the terrestrial natural product royleanone.220 A formal total synthesis of racemic 9isocyanopupukaenane(290), which is a metabolite of a Hawaiian Hymeniacidon species and the nudibranch Phyllidiu ~a r i c o s a , ~~~ has been reported 222. A synthesis of axisonitrile-…”