The synthesis of trisubstituted cyclopentadienes and their reactivity in the intramolecular Diels–Alder reaction

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332

, 183 (1984).Recent advances and examples of the intramolecular Diels-Alder reaction are summarized and applications to the total synthesis of natural products, both completed and in progress, noted. A detailed discussion of trienes leading to bicyclo[4.3.0]nonene skeletons is followed by examples of bicyclo[4.4.0]decenes and adducts arising from orthoquinodimethane precursors. Cycloadditions affording bicyclo[n.4.0] systems and bridged-ring adducts from cyclic dienes conclude this survey which is followed by a discussion of unreactive trienes and a brief analysis of synthetic strategy to complete the review. ALEX G. FALLIS. Can. J. Chem. 62, 183 (1984).On rCsume les recents dCveloppements et des exemples de rtaction de Diels-Alder intramolCculaire et on note leur utilisation dans la synthese des produits naturels dCjh effectuCs de m&me que dans celles qui sont en cours. Une discussion dCtaillCe des triknes conduisant aux squelettes bicyclo [Traduit par le journal]

Section: Bridged Ring Adducts (Cyclic Dienes)mentioning

confidence: 99%

The intramolecular Diels–Alder reaction: recent advances and synthetic applications

Fallis¹

1984

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332

“…In spite of considerable recent attention, the subtle substituent effects governing intramolecular Diels-Alder reactions are still imperfectly understood (10,11,19,(24)(25)(26)(27)(28)(29)(30). The key cycloaddition steps in the syntheses above were dia~tereos~ecific and were clearly dominated by the presence of the benzyl ether substituent and its orientation.…”

Section: Discussionmentioning

confidence: 99%

A general intramolecular Diels–Alder approach to tricyclic sesquiterpenes: stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene

Antczak¹,

Kingston²,

Fallis³

et al. 1987

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Stereoselective total syntheses of (*)-sinularene and (*)-5-epi-sinularene are described. The sequence employs a "blocked" (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550°C) completes the synthesis of (2)-sinularene in 12 steps from aldehyde 7. A parallel series of reactions employing the isopropyl triene epimer 13a affords (2)-5-epi-sinularene. X-ray analyses of the triene 13a and the adduct 14a are also reported.

“…cyclopentadienes A-C, the cycloadditions will proceed to give the fused ring product D rather than the isomeric bridged ring or Bredt olefin adducts E and F (7,8,12). Our earlier investigations revealed that the cycloheptane ring could not be generated directly and that ultimately a ring expansion would be required (7).…”

Section: Can I Chem \mentioning

confidence: 99%

“…Our earlier investigations revealed that the cycloheptane ring could not be generated directly and that ultimately a ring expansion would be required (7). In addition, it was established that carrying the dimethylhexenyl substituent caused difficulties, due to competing ene reactions during the cycloaddition step.…”

Section: Can I Chem \mentioning

confidence: 99%

“…In a retrosynthetic sense the double disconnection of the cyclohexene ring in gascardic acid would, in principle, allow the construction of the tricyclic framework by an intramolecular DielsAlder cycloaddition 2 to 1. However, cyclizations in which the diene and dienophile are linked by five atoms are difficult, particularly in carbocyclic systems (7)(8)(9). In addition, for retigeranic acid (3), a ring contraction of the cyclohexanone and the expulsion, from an unactivated center, of the extra carbon atom would be required.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A stereocontrolled intramolecular cycloaddition – sigmatropic rearrangement approach to a tricyclo[7.4.0^1,6.0^1,10]tridecane precursor for (±) gascardic acid

Bérubé¹,

Fallis²

1991

Self Cite

. Can. J. Chem. 69,77 (199 1). A general intramolecular Diels-Alder anionic oxy-Cope strategy for the synthesis of tricyclic skeletons and its application to the preparation of the gascardic acid precursor 21 is described. In situ generation of the appropriate cyclopentadiene 9 by isomerization (Et3N) afforded the [4+2] adduct directly or with EtA1Cl2 as catalyst. The requisite potassium salt of the 1,5 diene 16 rearranged with concomitant epimerization at 67OC to the fused ring ketone 18. Selective allylic oxidation and reduction provided 21.Key words: Diels-Alder, oxy-Cope, sesterterpene, synthesis, cycloaddition.