β-(Trimethylsilyl)ethoxymethyl chloride. A new reagent for the protection of the hydroxyl group

Lipshutz, Bruce H.; Pegram, Joseph J.

doi:10.1016/s0040-4039(00)78684-9

Cited by 187 publications

(71 citation statements)

References 15 publications

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“…[55, 56,57] The introduction of the allyl protecting group was significantly less straight-forward, but the easily accessible MOM and SEM ethers were converted into the aryllithium reagents by reaction with n-butyllithium in diethyl ether at -78°C. Reaction with tricarbonyl(η 5 -1,4-dimethoxycyclohexadienyl)iron hexafluorophosphate 4 in dichloromethane [58] at -100°C gave the exo [59] products 6a and 6b in about 50-65 % yield.…”

Section: Resultsmentioning

confidence: 99%

Electrophilic C₁₂ Building Blocks for Alkaloids: 1,1 Iterative Organoiron‐Mediated Routes to (±)‐Lycoramine and (±)‐Maritidine

2011

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Aryllithium reagents generated from protected 6‐bromoguaiacol and 2‐bromo‐4,5‐dimethoxybenzyl alcohol derivatives were used to prepare ortho‐substituted (1‐arylcyclohexadienyl)iron(1+) electrophiles. These were treated with Na+[Me3SiCH2CH2O2CCHCN]– to build aryl‐substituted quaternary centres in new examples of 1,1 iterative {[η4] → [η5]+ → [η4] → [η5]+ → [η4]} reaction sequences, which make use of the electrophilicity of the metal complex in two key carbon–carbon bond‐formation steps. MOM protection of the guaiacol was better than SEM for access to the lycoramine skeleton, and TBDPS was best for maritidine. Decomplexation, hydrolysis, and cyclisation completed formal total syntheses of the Amaryllidaceae alkaloids (±)‐lycoramine and (±)‐marididine, establishing the compatibility of the organoiron method with the presence of ortho substituents on the aryl group, and nucleophile addition ipso to the substituted arene.

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Section: Resultsmentioning

confidence: 99%

Electrophilic C₁₂ Building Blocks for Alkaloids: 1,1 Iterative Organoiron‐Mediated Routes to (±)‐Lycoramine and (±)‐Maritidine

2011

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“…6 This could then give the ketene intermediate 19 which would lead to allene 20 by the attack of a water molecule at the carbonyl carbon. And the allenic intermediate 20 might be stabilized by the α-silyl group and tautomerize easily to the stable silylenone 21.…”

Section: Resultsmentioning

confidence: 99%

Unusual Transformation of Cyclobutenediones into Butenolides

Lee¹,

Moore²

2003

Journal of the Korean Chemical Society

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“…Reduction of 19-THP-19-hydroxyandrostenedione (12) (30) with LiAl (O-t-butyl)3H (31) gave the known (30) 19-THP-19-hydroxytestosterone (13). This compound was then protected as the 17-SEM ether 14(87% yield from 19-THP-19-hydroxyandrostenedione with SEM chloride and Hunig's base (32)] and converted to the unstable hydrazone derivative, using 2,4,6-triisopropylbenzenesulfonylhydrazide and HCl. The unpurified hydrazone was treated with n-butyllithium and TMEDA in hexane to afford the bis-protected homoannular diene 15 in 61% yield.…”

Section: Resultsmentioning

confidence: 99%

Conversion of a 3-desoxysteroid to 3-desoxyestrogen by human placental aromatase.

Cole

Bean

Robinson

1990

Proc. Natl. Acad. Sci. U.S.A.

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Human placental aromatase is a cytochrome P.450 enzyme system which converts androgens to estrogens by three successive oxidative reactions. The first two steps have been shown to be hydroxylations at the androgen 19-carbon, but the third step remains unknown. A leading theory for the third step involves ferric peroxide attack on the 19-oxo group to produce a 19,19-hydroxyferric peroxide intermediate and subsequent collapse to estrogen. We had previously developed a nonenzymatic peroxide model reaction which was based on the above-mentioned theory, and we demonstrated the importance of 3-ketone enolization in facilitating aromatization. This study discusses the synthesis and nonenzymatic and enzymatic study of a 3-desoxy-2,4-diene-19-oxo androgen analogue. This compound was found to be a potent nonenzymatic model substrate and competitive inhibitor of aromatase (K1 = 73 nM).Furthermore, in an unprecedented event, this compound served as a substrate for aromatase, with conversion to the corresponding 3-desoxyestrogen.

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β-(Trimethylsilyl)ethoxymethyl chloride. A new reagent for the protection of the hydroxyl group

Cited by 187 publications

References 15 publications

Electrophilic C₁₂ Building Blocks for Alkaloids: 1,1 Iterative Organoiron‐Mediated Routes to (±)‐Lycoramine and (±)‐Maritidine

Electrophilic C₁₂ Building Blocks for Alkaloids: 1,1 Iterative Organoiron‐Mediated Routes to (±)‐Lycoramine and (±)‐Maritidine

Unusual Transformation of Cyclobutenediones into Butenolides

Conversion of a 3-desoxysteroid to 3-desoxyestrogen by human placental aromatase.

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β-(Trimethylsilyl)ethoxymethyl chloride. A new reagent for the protection of the hydroxyl group

Cited by 187 publications

References 15 publications

Electrophilic C12 Building Blocks for Alkaloids: 1,1 Iterative Organoiron‐Mediated Routes to (±)‐Lycoramine and (±)‐Maritidine

Electrophilic C12 Building Blocks for Alkaloids: 1,1 Iterative Organoiron‐Mediated Routes to (±)‐Lycoramine and (±)‐Maritidine

Unusual Transformation of Cyclobutenediones into Butenolides

Conversion of a 3-desoxysteroid to 3-desoxyestrogen by human placental aromatase.

Contact Info

Product

Resources

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Electrophilic C₁₂ Building Blocks for Alkaloids: 1,1 Iterative Organoiron‐Mediated Routes to (±)‐Lycoramine and (±)‐Maritidine

Electrophilic C₁₂ Building Blocks for Alkaloids: 1,1 Iterative Organoiron‐Mediated Routes to (±)‐Lycoramine and (±)‐Maritidine