Steroids and Related Natural Products. XI. Reduction of Esters to Ethers

George R. Pettit; David M. Piatak

doi:10.1021/jo01053a054

Steroids and Related Natural Products. XI. Reduction of Esters to Ethers

George R. Pettit, David M. Piatak

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Abstract

Direct reduction of dihydroabietic γ-lactone (la), the isomeric butyl esters (IIIb-d) of cholanic acid, and f-butyl- 5a-pregnane 20S-carboxylic acid (Va) to the corresponding ethers (Ib, IVa, IVc, IVd, and VI) has been accomplished. Reduction was carried out using a reagent prepared from sodium borohydride and boron trifluoride, in diglyme-tetrahydrofuran. Boron trifluoride with either lithium aluminum hydride or lithium borohydride proved less satisfactory. Increasing conversion of the butyl esters (IIIb-d) to ethers (7-76% yield) was observed as the alcohol group varied from normal to tertiary. Similar reduction of 3β-formyloxy-5aα-cholestane and 3β-formvloxy-5aα-lanostane (VIIa) gave the corresponding 3β-methoxy steroids. The sensitivity of this unique ester → ether eduction reaction to structural variations in the ester group has been discussed.

Original language	English (US)
Pages (from-to)	2127-2130
Number of pages	4
Journal	Journal of Organic Chemistry
Volume	27
Issue number	6
DOIs	https://doi.org/10.1021/jo01053a054
State	Published - Jun 1 1962
Externally published	Yes

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Organic Chemistry

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title = "Steroids and Related Natural Products. XI. Reduction of Esters to Ethers",

abstract = "Direct reduction of dihydroabietic γ-lactone (la), the isomeric butyl esters (IIIb-d) of cholanic acid, and f-butyl- 5a-pregnane 20S-carboxylic acid (Va) to the corresponding ethers (Ib, IVa, IVc, IVd, and VI) has been accomplished. Reduction was carried out using a reagent prepared from sodium borohydride and boron trifluoride, in diglyme-tetrahydrofuran. Boron trifluoride with either lithium aluminum hydride or lithium borohydride proved less satisfactory. Increasing conversion of the butyl esters (IIIb-d) to ethers (7-76% yield) was observed as the alcohol group varied from normal to tertiary. Similar reduction of 3β-formyloxy-5aα-cholestane and 3β-formvloxy-5aα-lanostane (VIIa) gave the corresponding 3β-methoxy steroids. The sensitivity of this unique ester → ether eduction reaction to structural variations in the ester group has been discussed.",

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year = "1962",

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T1 - Steroids and Related Natural Products. XI. Reduction of Esters to Ethers

AU - Pettit, George R.

AU - Piatak, David M.

PY - 1962/6/1

Y1 - 1962/6/1

N2 - Direct reduction of dihydroabietic γ-lactone (la), the isomeric butyl esters (IIIb-d) of cholanic acid, and f-butyl- 5a-pregnane 20S-carboxylic acid (Va) to the corresponding ethers (Ib, IVa, IVc, IVd, and VI) has been accomplished. Reduction was carried out using a reagent prepared from sodium borohydride and boron trifluoride, in diglyme-tetrahydrofuran. Boron trifluoride with either lithium aluminum hydride or lithium borohydride proved less satisfactory. Increasing conversion of the butyl esters (IIIb-d) to ethers (7-76% yield) was observed as the alcohol group varied from normal to tertiary. Similar reduction of 3β-formyloxy-5aα-cholestane and 3β-formvloxy-5aα-lanostane (VIIa) gave the corresponding 3β-methoxy steroids. The sensitivity of this unique ester → ether eduction reaction to structural variations in the ester group has been discussed.

AB - Direct reduction of dihydroabietic γ-lactone (la), the isomeric butyl esters (IIIb-d) of cholanic acid, and f-butyl- 5a-pregnane 20S-carboxylic acid (Va) to the corresponding ethers (Ib, IVa, IVc, IVd, and VI) has been accomplished. Reduction was carried out using a reagent prepared from sodium borohydride and boron trifluoride, in diglyme-tetrahydrofuran. Boron trifluoride with either lithium aluminum hydride or lithium borohydride proved less satisfactory. Increasing conversion of the butyl esters (IIIb-d) to ethers (7-76% yield) was observed as the alcohol group varied from normal to tertiary. Similar reduction of 3β-formyloxy-5aα-cholestane and 3β-formvloxy-5aα-lanostane (VIIa) gave the corresponding 3β-methoxy steroids. The sensitivity of this unique ester → ether eduction reaction to structural variations in the ester group has been discussed.

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JO - Journal of Organic Chemistry

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ER -

Steroids and Related Natural Products. XI. Reduction of Esters to Ethers

Abstract

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