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Volumn , Issue 9, 1999, Pages 1491-1494

Chemoenzymatic and enantiodivergent routes to highly functionalised steroidal nuclei

Author keywords

Anionic oxy Cope rearrangement; Diels Alder cycloaddition; Enantiodivergent synthesis; Steroids

Indexed keywords

CATECHOL DERIVATIVE; STEROID;

EID: 0032875337     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1999-2856     Document Type: Article
Times cited : (15)

References (53)
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    • For reviews on the applications of cis-1,2-dihydrocatechols in synthesis see: (a) Carless, H. A. J. Tetrahedron Asym., 1992, 3, 795;
    • (1992) Tetrahedron Asym. , vol.3 , pp. 795
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    • For an excellent discussion of the full range of aromatic metabolites that are available via microbial oxidation techniques see: Boyd, D. R.; Sheldrake, G. N. Nat. Prod. Rep., 1998, 15, 309.
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    • Boyd, D.R.1    Sheldrake, G.N.2
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    • We have described the application of the synthetic strategy reported here-in to the preparation of several enantiopure cis-decalins: Banwell, M. G.; Dupuche, J. R. Chem. Commun, 1996, 869.
    • (1996) Chem. Commun , pp. 869
    • Banwell, M.G.1    Dupuche, J.R.2
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    • note
    • 3/mmol of 2) and p-toluenesulfonic acid monohydrate (1 mole% w.r.t 2). Stirring was continued for 3.0 h then the reaction mixture was quenched with triethylamine (ca. 0.70 mole equiv.). The THF and excess triethylamine were removed on a rotary evaporator (bath temp. < 20 °C) and the residue subjected to a normal extractive work-up using ether and 2 M aqueous NaOH.
  • 32
    • 0345026954 scopus 로고    scopus 로고
    • note
    • This diol protecting group was chosen because of the difficulties (see Footnote 12) associated with removing an acetonide group at a later stage in the synthesis. Interestingly, the bis-TBDMS-ether of 2 failed to engage in a Diels-Alder cycloaddition reaction with p-benzoquinone.
  • 33
    • 0345026953 scopus 로고    scopus 로고
    • note
    • Unless otherwise specified, all optical rotations were determined at 20 °C using chloroform as solvent.
  • 34
    • 0345458087 scopus 로고    scopus 로고
    • note
    • All new compounds had spectroscopic data (IR, NMR, mass spectrum) consistent with the assigned structure. Satisfactory combustion and/or high resolution mass spectral analytical data were obtained for new compounds and/or suitable derivatives.
  • 36
    • 0344164375 scopus 로고    scopus 로고
    • note
    • Hydrolysis of the acetonide analogue, i, of compound 7 could only be achieved under much more forcing conditions. As a result, varying mixtures of diol 8 and the rearranged/undesired triol ii were obtained. equation presented
  • 38
    • 0345026951 scopus 로고    scopus 로고
    • note
    • This de-oxygenation sequence was implemented so as to facilitate nucleophilic addition of a cyclopentenyl moiety to the C-2 carbonyl from the α-face and thereby establish the stereochemistry required for anionic oxy-Cope rearrangement. In principle, Mitsunobu inversion of the hydroxyl group within the acyloin would then allow the nucleophilic addition to take place in the desired sense and ultimately lead to incorporation of oxygen at C-11 in the steroid nucleus. This option would be of interest for the purposes of preparing corticosteroids.
  • 41
    • 0345458086 scopus 로고    scopus 로고
    • note
    • A reductive debomination step is required because the presence of the bridgehead bromine interferes with the anionic oxy-Cope rearrangement reaction that follows by facilitating what are believed to be Eschenmoser/Grob-like fragmentation reactions.
  • 42
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    • 11 The resulting mixture of racemic allylic alcohols was then resolved by enantioselective trans-esterification using the Novo Nordisk A/S SP-435 biocatalyst (Johnson, C. R. and Sakaguchi, H. Synlett, 1992, 813). O-Methylation of the S-alcohol with MeI/NaH in THF was followed by conversion into the organocerium 13 using standard methods (Paquette, L. A. In Encyclopedia of Reagents for Organic Synthesis. Paquette, L. A. Ed.; Wiley, Chichester, 1995, 2, 1031). Compounds ent-13 and (±)-13 were prepared in similar manner.
    • (1992) Tetrahedron Lett. , vol.33 , pp. 917
    • Johnson, C.R.1    Adams, J.P.2    Braun, M.P.3    Senanayake, C.B.W.4    Wovkulich, P.M.5    Uskokovic, M.R.6
  • 43
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    • 11 The resulting mixture of racemic allylic alcohols was then resolved by enantioselective trans-esterification using the Novo Nordisk A/S SP-435 biocatalyst (Johnson, C. R. and Sakaguchi, H. Synlett, 1992, 813). O-Methylation of the S-alcohol with MeI/NaH in THF was followed by conversion into the organocerium 13 using standard methods (Paquette, L. A. In Encyclopedia of Reagents for Organic Synthesis. Paquette, L. A. Ed.; Wiley, Chichester, 1995, 2, 1031). Compounds ent-13 and (±)-13 were prepared in similar manner.
    • (1992) Synlett , pp. 813
    • Johnson, C.R.1    Sakaguchi, H.2
  • 44
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    • Paquette, L. A. Ed.; Wiley, Chichester, Compounds ent-13 and (±)-13 were prepared in similar manner
    • 11 The resulting mixture of racemic allylic alcohols was then resolved by enantioselective trans-esterification using the Novo Nordisk A/S SP-435 biocatalyst (Johnson, C. R. and Sakaguchi, H. Synlett, 1992, 813). O-Methylation of the S-alcohol with MeI/NaH in THF was followed by conversion into the organocerium 13 using standard methods (Paquette, L. A. In Encyclopedia of Reagents for Organic Synthesis. Paquette, L. A. Ed.; Wiley, Chichester, 1995, 2, 1031). Compounds ent-13 and (±)-13 were prepared in similar manner.
    • (1995) Encyclopedia of Reagents for Organic Synthesis , vol.2 , pp. 1031
    • Paquette, L.A.1
  • 45
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    • suggested that high α-face selectivity could be achieved in the nucleophilic cyclopentenylation of 12 or ent-12 through proper matching with the appropriate enantiomer of the nucleophile 13
    • Reaction of ketone 12 with (±)-13 gave only two of four possible diastereoisomeric 3°-alcohols and only one of these (the chromatographically less mobile one, viz. 14) underwent anionic oxy-Cope rearrangement to give enone 1. The other 3°-alcohol (see structure iii, Footnote 19) was recovered unchanged from the rearrangement reaction. These observations together with related ones made by Paquette and co-workers (Doyon, J.; He, W.; Paquette, L. A. J. Org. Chem. 1994, 59, 2033) suggested that high α-face selectivity could be achieved in the nucleophilic cyclopentenylation of 12 or ent-12 through proper matching with the appropriate enantiomer of the nucleophile 13.
    • (1994) J. Org. Chem. , vol.59 , pp. 2033
    • Doyon, J.1    He, W.2    Paquette, L.A.3
  • 46
    • 0344595943 scopus 로고    scopus 로고
    • note
    • max = 120.0°), 1296 with I > 3σ(I); R = 0.034, Rw = 0.045, GOF = 2.62. Data were measured on a Rigaku AFC6R rotating anode diffractometer (graphite crystal monochromator, λ = 1.54178 Å). Refinement was by full-matrix least squares analysis on F using the teXsan Structure analysis Software of Molecular Structure Corporation. Crystal structure data have been deposited with the Cambridge Crystallographic Data Centre (CCDC) and can be obtained by directing enquiries to the following address: The Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, United Kingdom.
  • 51
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    • note
    • 3 requires 300.1725.
  • 52
    • 0344164374 scopus 로고    scopus 로고
    • note
    • The illustrated configuration at C-14 (steroid numbering) in this compound follows from the stereoelectronic requirements of the anionic oxy-Cope rearrangement process (see reference cited in footnote 18).
  • 53
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    • Oxford: Oxford, to this compound should permit introduction, in a diastereofacially selective manner, of both a C-13 methyl group and a C-17 "side-chain", which are observed in the vast majority of naturally occurring steroids
    • In principle, application of a three-component coupling reaction (see Taylor, R. J. K. Organocopper Reagents - A Practical Approach; Oxford: Oxford, 1994) to this compound should permit introduction, in a diastereofacially selective manner, of both a C-13 methyl group and a C-17 "side-chain", which are observed in the vast majority of naturally occurring steroids.
    • (1994) Organocopper Reagents - A Practical Approach
    • Taylor, R.J.K.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.