Stereocontrolled synthesis of (±)-methyl 3,6-epoxy-4,6,8-triethyl-2,4,9-dodecatrienoate, a major metabolite of Caribbean sponge, Plakortis halichondrioides, using reactions of alkylidenecarbenes in one pot

Transition metals in organic synthesis: Highlights for the year 2005

“…Intramolecular rhodium-catalyzed carbon-hydrogen bond insertions via decomposition of diazo compounds forming four to six membered rings were used in a number of synthetic applications, for example, toward (+)-sulcatine G [720], ␤-and ␥-lactams [721], baclophen and GABOB [722], (+)-␤-herbertenol [723], 9-isocyanoneopupukeanane [724], (−)-rolipram [725], toward cyperanes [726], chiral ␥-lactams [727], viridenomycin [728] and 3,6-epoxy-4,6,8-triethyl-2,4,9-dodecatrienoate [729]. An intermolecular rhodium-catalyzed aromatic carbon-hydrogen bond insertion was used in a synthesis of derrusnin [730].…”

Recent Advances in Total Synthesis of Bioactive Furo[3,2‐b]furanone Natural Products

“…The synthesized material, however, turned out to be (±)‐8‐ epi ‐plakortone E (147) (Scheme ) . The diol 148 was elaborated to the diol ether 149 via known procedure . IBX oxidation of the 2°‐OH followed by reaction with TMSCLiN 2 afforded dihydrofuran 150 via C−H insertion reaction of the incipient alkylidene carbene intermediate.…”

“…[54] The diol 148 was elaborated to the diol ether 149 via known procedure. [55] IBX oxidation of the 2°-OH followed by reaction with TMSCLiN 2 afforded dihydrofuran 150 via CÀ H insertion reaction of the incipient alkylidene carbene intermediate. Allylic oxidation of 150 (to the corresponding butenolide), DIBALÀ H reduction, introduction of the acetic acid side chain with Ph 3 P=CHCO 2 CH 3 and ester hydrolysis afforded the carboxylic acids 151 a,b (1 : 1 mixture).…”

Efficient Synthetic Routes to (±)‐Hippolachnin A, (±)‐Gracilioethers E and F and the Alleged Structure of (±)‐Gracilioether I

“…Such structural features, together with the bioactivity already observed with some of these compounds (e.g., 7 , with an antifungal MIC value of 0.41 μ m ), made the gracilioethers attractive synthetic targets. In 2005, Ohira reported the first route to 1 (without mentioning its identity as a natural product) as an intermediate for a related natural product. Then, in late 2014, Rasik and Brown reported the first synthesis of (±)‐gracilioether F ( 5 ), which was soon followed (in early 2015) by the first synthesis of (±)‐hippolachnin A ( 7 ) by Carreira and co‐workers.…”

“…Use of the sequence reported by Ohira with slight modification (i.e., using 19 /TiCl 4 instead of Ph 3 P=CHCO 2 Me in synthesis of 20 ) converted 1 into 21 (Scheme ). However, the subsequent intramolecular photo‐induced [2+2] cycloaddition of 21 did not occur as expected; irradiation with UV light (mercury lamp) resulted in only configurational change of the C−C double bond in the side‐chain.…”