Perbenzoic Acid Oxidation of 20-Ketosteroids and the Stereochemistry of C-17<sup>1</sup>

Gallagher, T. F.; Kritchevsky, Theodore H.

doi:10.1021/ja01158a062

Cited by 47 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…( 8 ) To further investigate the mechanism of the reaction, in this study we examined the stereochemical course of catalysis at C1 and C2 of 2-HEP. If the reaction proceeds by a hydroperoxylation mechanism, net inversion of configuration should occur at C1 with retention during the Criegee rearrangement( 13 ) and inversion in the hydrolysis step.…”

mentioning

confidence: 99%

On the Stereochemistry of 2-Hydroxyethylphosphonate Dioxygenase

et al. 2011

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

On the Stereochemistry of 2-Hydroxyethylphosphonate Dioxygenase

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The position of labeling on the stereochemistry of the 20-keto stereoid oxidation. [62] was determined by reducing the ester to phenol and benzyl alcohol with lithium aluminium hydride (Scheme 7). The resulting phenol contained no 18 O atom whereas the benzyl alcohol contained 93% of the labeled oxygen atom of the starting material indicating that the 18 O atom of benzo- of phenyl benzoate.…”

mentioning

confidence: 99%

100 Years of Baeyer–Villiger Oxidations

Renz

Meunier²

1999

Eur. J. Org. Chem.

543

307

View full text Add to dashboard Cite

In the present review, we report the discovery of the formation of esters and lactones by oxidation of ketones with a peroxide derivative, namely the Baeyer–Villiger reaction. This reaction was first reported by Adolf von Baeyer and Victor Villiger a century ago in 1899, just one year after the oxidant they used (KHSO5) has been described. Furthermore, Baeyer and Villiger established the composition of this new inorganic peroxide and showed that its instability was the reason of a controversy between several European chemists between 1878 and 1893. For the first 50 years the mechanism of the Baeyer–Villiger reaction was a matter of debate. A side product, 1,2,4,5‐tetraoxocyclohexane, was ruled out as an intermediate in the ester formation by Dilthey. Criegee postulated a nucleophilic attack of the oxidant on the carbonyl group. This mechanism was confirmed by von E. Doering by a labeling experiment with [18O]benzophenone. The rearrangement step occurs with retention of the stereochemistry at the migrating center. The competitive migration and the rate‐determining step are also discussed in this review.

show abstract

“…2 Inspection of models indicated that / I only a 12P-hydroxy function would form an internal hydrogen bond to the 20-carbonyl group (minimal distance: 2 A). 3 These data made possible an unambiguous assignnlent of configuration for the epin~eric tertiary alcohols IV and VI and proved that the attaclr of methyl magnesium iodide on pregnan-12-ones proceeded mainly from the p-side of the steroid molecule, contrary, -in this case, to the well-known "rule of rear-attack" in steroids (3,4). The validity of the assignment of configuration a t the 12-position was confirmed as follows: T h e tertiary alcohol VI on treatment with acetic acid, acetic anhydride, and p-toluenesulpl~onic acid (5) gave the acetate VIa, m.p.…”

mentioning

confidence: 83%

Steroids: Ii. The Stereochemistry of the Addition of Grignard Reagents to 12-Ketosteroids

Nagarajan¹,

Just²

1961

Can. J. Chem.

View full text Add to dashboard Cite

The action of methyl magnesium iodide on 3a,20cu-diacctoxyprcgna1~-12-one (IIa) led to thc formation of the cpimeric 12-methyl-12-hydroxypreg~ianes 111 and V, in which the 12a-hydrosy-120-methyl isonier 111 predominated.Infrared measurements on the corresponding 12-hydroxy-12-rnethyIpreg1ia1~e-3,20-dioi~es VI and IV permitted unambiguous assignment of configuration a t C13.The pregnanedione IV was transformed to 120-hydroxy-12cu-methylprogesterone.In the first paper of this series (1) we described the conversion of pregnane-3aI12a,20P-trio1 to 12a-hydroxy-12P-methylprogesterone. We should now like to report on the conversion of pregnane-3a,12a,20a-triol (I) t o the epi~neric 12-hydroxy-12-methyl-3,20-pregnanediones IV and VI and on the conversion of the former to 12P-hydroxy-12a-inethylprogesterone (VII).Partial succinylation (I) of pregnane-3a,l2a,2Oa-triol (I) with succinic anhydride in pyridine, followed by methylation of the hemisuccinate with ethereal diazomethane, afforded a 91% yield of pregnane-3a,12a,20a-triol 3,20-bis-methyl succinate (Ia). Oxidation of Ia with chromium trioxide in acetic acid gave the corresponding 12-ketone IIb. Our experience in the 20P-hydroxy series (1) indicated t h a t the reaction of methyl magnesium iodide on pregnan-12-ones proceeded in better yield in the presence of a 20-acetate group rather than a 20-succinate function. Hence, the disuccinoxy ketone IIb was hydrolyzed with methanolic potassiuin hydroxide to 3a,20a-dihydroxypregnan-12-one (11) and the latter acetylated with acetic anhydride in pyridine. T h e resulting diacetoxy ltetone I I a was treated with an excess of ethereal methyl magnesium iodide for 20 hours. Acetylation, chromatography, alkaline hydrolysis, and repeated crystallizations gave the epi~neric 12-inethylpregnane-3a,12,20a-triols I11 and V. T h e mono-, di-, and triacetates IIIa-c and Va were prepared and interrelated (see Experimental). Since the separation of the epiineric triols I11 and V by crystallization was tedious and incomplete, the mother liquors of the crystallization of the Grignard product containing the epimeric triols 111 and V were oxidized with chromic oxide in acetic acid. Chromatography on alumina of the oxidation product afforded 12P-methyl-12a-hydroxypregnane-3,20-dione (VI) and its 12a-methyl isomer IV. The total yield of the Grignard adducts 111 (VI) and V (IV) was 60.5% and 25.0% respectively. T h e hydroxy ltetone VI was identical with the 12~-methyl-l2a-hydroxypregnane-3,2O-dione, isolated previously in the 20P-series (1) in 73y0 yield as the only product of the correspoilding Grignard reaction. The infrared spectrum of this hydrosy dilcctone showed bands a t 3680 cm-I (free 01-1) and 1713 cm-I (3,20-dione) .? 1Manzrscript received Janzrary 6 , 1961. Contribution fronz the

show abstract

Perbenzoic Acid Oxidation of 20-Ketosteroids and the Stereochemistry of C-17¹

Cited by 47 publications

References 0 publications

On the Stereochemistry of 2-Hydroxyethylphosphonate Dioxygenase

On the Stereochemistry of 2-Hydroxyethylphosphonate Dioxygenase

100 Years of Baeyer–Villiger Oxidations

Steroids: Ii. The Stereochemistry of the Addition of Grignard Reagents to 12-Ketosteroids

Contact Info

Product

Resources

About

Perbenzoic Acid Oxidation of 20-Ketosteroids and the Stereochemistry of C-171

Cited by 47 publications

References 0 publications

On the Stereochemistry of 2-Hydroxyethylphosphonate Dioxygenase

On the Stereochemistry of 2-Hydroxyethylphosphonate Dioxygenase

100 Years of Baeyer–Villiger Oxidations

Steroids: Ii. The Stereochemistry of the Addition of Grignard Reagents to 12-Ketosteroids

Contact Info

Product

Resources

About

Perbenzoic Acid Oxidation of 20-Ketosteroids and the Stereochemistry of C-17¹