Synthetic studies toward complex diterpenoids. IX. New stereocontrolled synthetic route to some intermediates for diterpenoid alkaloids and C20 gibberellins

Ghatak, Usha Ranjan; Chakrabarty, Sephali

doi:10.1021/jo00869a002

Cited by 21 publications

(3 citation statements)

References 6 publications

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“…Me' ' 10 Me/ \COCH=N2 12 13 From the results of the TFA-catalysed reactions of the diazoketones l a d (Table 1) it is clear that irrespective of the nature of the aromatic substituents in compounds la-d, the Ar,-4 participation by the protonated diazocarbonyl group constitutes a substantial pathway in the acid-catalysed reaction. This, as has been frequently observed in n-bond 2-5 (cf.…”

Section: 'mentioning

confidence: 99%

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Condensed cyclic and bridged-ring systems. Part 15. Acid-catalysed intramolecular alkylations in 1-diazoacetyl-1,2,3,4-tetrahydro-9-methoxy-1-methylphenanthrenes

Pal¹,

Banik²,

Ghatak³

1994

J. Chem. Soc., Perkin Trans. 1

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Section: 'mentioning

confidence: 99%

“…The initial fractions gave compound 4c as a solid (240 mg, 45%); m.p. 13 Catalytic hydrogenation of 3c to l l c . The pentaleno ketone 3c (200 mg, 0.07 mmol) was hydrogenated in the same way as described for compound 3b to give l l c (16 mg, 88%) as an oil, identical in all respects (IR, 'H NMR, GLC) with an authentic sample.…”

Section: 'mentioning

confidence: 99%

Condensed cyclic and bridged-ring systems. Part 15. Acid-catalysed intramolecular alkylations in 1-diazoacetyl-1,2,3,4-tetrahydro-9-methoxy-1-methylphenanthrenes

Pal¹,

Banik²,

Ghatak³

1994

J. Chem. Soc., Perkin Trans. 1

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“…Transformation of the cr-Keto y-Lactonic Ester (Ha) to 8,9,10,11,.-To a magnetically stirred solution of compound (15a) (325 mg, 0.99 mmol) in CH,Cl, (25 ml) at 10-15 "C, aqueous NaOH (25 ml, 10%) was added followed by aqueous H,O, (10 ml, 30%). After 1 h, second portions of aqueous NaOH (25 ml, 10%) and aqueous H,O, (10 ml, 30%) were added.…”

Section: Oxidation Of the Dihydroxymentioning

confidence: 99%

Acid-catalysed intramolecular C-alkylation in β,γ-unsaturated diazomethyl ketones. Part 4. Synthesis of functionalised hydrophenanthrene and benzocyclodecenone derivatives via novel fragmentation reactions, and X-ray structural analyses of two angularly substituted hydrophenanthrene derivatives

Saha¹,

Roy²,

Satyanarayana³

et al. 1985

J. Chem. Soc., Perkin Trans. 1

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Intramolecular Reactions of Diazocarbonyl Compounds

Burke

Grieco

1979

Organic Reactions

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Since the demonstration by Stork and Ficini in 1961 that unsaturated diazoketones undergo intramolecular cyclization to form cyclopropanes the intramolecular reactions of α‐diazocarbonyl compounds have been extensively studied under thermal, catalytic, and photochemical conditions. Intramolecular cyclization of α‐carbonyl carbenes and carbenoids has found widespread application to the synthesis of theoretically interesting compounds such as bullvalene, twistane, bridged annulenes, and barbaralone, as well as syntheses of natural products such as sabinene, sirenin, α‐chamigrene, and phyllocladene. The reaction has also allowed the construction of several intriguing polycyclic systems that were unattainable by alternative methods. A recent review has covered the reactions of diazoacetic esters with alkenes, alkynes, heterocyclics, and aromatic compounds. Unsaturated alkoxycarbonyl carbenes (:CHCO 2 R) and unsaturated carbonyl carbenes (:CHCOR) (where R contains either aromatic or olefinic groups), which are considered to be intermediates in the absence of catalyst, have been the subject of several other reviews. A review concerning photochemically, thermally, and catalytically induced Wolff rearrangements of α‐diazocarbonyl compounds has recently appeared. However to date no comprehensive review has appeared which demonstrates the synthetic potential of α‐diazocarbonyl insertion and addition reactions. In reviewing the reactions of α‐diazocarbonyl compounds chosen not to include certain peripheral topics such as intermolecular reactions, intramolecular dimerization of bis(α‐carbonyl carbenoids) to give diacyl cycloolefins and intramolecular trimerizations of tris(α‐keto carbenoids), affording triacylcyclopropanes are not included. Also excluded are base‐catalyzed reactions of α‐diazocarbonyl compounds and certain ring‐contraction reactions involving CC bond insertion of intermediate α‐ketocarbenes. The topics included in this report are the intramolecular reactions of α‐carbonyl carbenes and carbenoids with olefinic and aromatic unsaturation, with CH bonds, and with CC and NH single bonds. Also included are acid‐catalyzed cyclization reactions of α‐diazoketones.

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Synthetic studies toward complex diterpenoids. IX. New stereocontrolled synthetic route to some intermediates for diterpenoid alkaloids and C20 gibberellins

Cited by 21 publications

References 6 publications

Condensed cyclic and bridged-ring systems. Part 15. Acid-catalysed intramolecular alkylations in 1-diazoacetyl-1,2,3,4-tetrahydro-9-methoxy-1-methylphenanthrenes

Condensed cyclic and bridged-ring systems. Part 15. Acid-catalysed intramolecular alkylations in 1-diazoacetyl-1,2,3,4-tetrahydro-9-methoxy-1-methylphenanthrenes

Acid-catalysed intramolecular C-alkylation in β,γ-unsaturated diazomethyl ketones. Part 4. Synthesis of functionalised hydrophenanthrene and benzocyclodecenone derivatives via novel fragmentation reactions, and X-ray structural analyses of two angularly substituted hydrophenanthrene derivatives

Intramolecular Reactions of Diazocarbonyl Compounds

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