A total synthesis of (±)-isocomene and (±) β-isocomene by an intramolecular ene reaction

Oppolzer, Wolfgang; Bättig, Kurt; Hudlický, Tomáš

doi:10.1016/0040-4020(81)80001-4

Cited by 59 publications

(16 citation statements)

References 38 publications

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“…Syntheses of monocyclic and bicyclic terpenes as 655, 658, and 660. [470] Wolff rearrangement was involved at a late, tricyclic stage in syntheses of isocomene, 656 Ǟ 657 Ǟ 658, [471] 3-oxosilphinene, [472] and pentalenene, 659 Ǟ 660. [473a] The linear triquinane capnellene (662), isolated from the soft coral Capnella imbricata, was synthesized by ring contraction of 661.…”

Section: Natural Products and Related Targetsmentioning

confidence: 99%

100 Years of the Wolff Rearrangement

2002

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The conversion of α‐diazo ketones into ketenes, and products derived therefrom, was discovered by Wolff in 1902. Major applications of the Wolff rearrangement, such as the Arndt−Eistert reaction (homologation of carboxylic acids) and the ring contraction of cyclic ketones, have been with us for some while. Nevertheless, substantial progress has been made recently. The reaction mechanism has been explored by means of matrix isolation, time‐resolved spectroscopy, and computation. Full retention of configuration of the migrating group has been established by using enantioselective chromatography. The Arndt−Eistert reaction has witnessed a renaissance in the field of natural products, in particular β‐amino acids and β‐peptides. Ring‐contracting Wolff rearrangements and ketene cycloadditions have been applied in syntheses of increasingly complex, biologically active target molecules. These accomplishments, as well as unsolved problems, are addressed in the present review. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

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Section: Natural Products and Related Targetsmentioning

confidence: 99%

100 Years of the Wolff Rearrangement

2002

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“…1,7-Octadien-3-one ( 2 ) was prepared in 70% overall yield by reaction of acrolin and Grignard reagent prepared from 5-bromo-1-pentene, followed by Jones oxidation. 7 …”

Section: Resultsmentioning

confidence: 99%

The Efficient and Enantiospecific Total Synthesis of Cyclopenta[b]phenanthrenes Structurally‐Related to Neurosteroids

Mei

Covey

2010

Adv Synth Catal

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We report an efficient synthesis of cyclopenta[b]phenanthrenes functionalized at C-3 and C-8 from an optically pure Hajos-Parrish ketone. The key step is a neutral alumina catalyzed Michael addition of a Hajos-Parrish ketone derivative (4) to 1,7-octadien-3-one (2) in 98% yield. This Michael addition product went through Krapcho decarbomethoxylation, aldol condensation, lithium liquid ammonia reduction, Wacker oxidation and acid catalyzed cyclization to form cyclopenta[b]phenanthrene (1a) in 37% overall yield for the 7 steps.

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“…Junione, 182 grandisol, 183 acanthodoral, 184 and oxetacin 23c bear a four-membered ring that were obtained by ring contraction of cyclopentanones. Although, a-oplopenone, 185 pentalenolactone E methyl ester, 186 silphinene, 187 isocomene, 188 pentalenene, 189 D 9(12) capnellene, 190 gibberellin A 1 , 191 polyandrane, 192 and Meloscine 193 relied in the contraction of diazo cyclohexanones. An isolated example of Wolff rearrangement in a diazo cycloheptanone was explored for the synthesis of camphorenone.…”

Section: Ring Contractions In Total Synthesismentioning

confidence: 99%