Hydroboration of Enol Acetates

Alfred Hassner; Ronald E. Barnett; P. Catsoulacos; S. H. Wilen

doi:10.1021/ja01038a039

Hydroboration of Enol Acetates

Alfred Hassner, Ronald E. Barnett, P. Catsoulacos, S. H. Wilen

University of Colorado Boulder

Research output: Contribution to journal › Article › peer-review

17 Scopus citations

Abstract

The directive effect of an acetoxy substituent in the hydroboration of olefins was examined. Cyclohexenyl acetate and 2-cholesten-3-ol acetate (7) yielded the expected diols, but in addition a considerable amount of monols was obtained. Cyclopentenyl acetate and 2-cholesten-3-ol benzoate gave only monols and none of the expected diol products. ∆¹⁶-17-Acetoxy steroid 6 gave a trans diol on hydroboration. The yield of monol from cyclohexenyl acetate was raised with increasing temperature and increasing amount of diborane. Pyridine borane-aluminum chloride gave solely cyclohexanol. It was shown that the monol derived from 7 did not result from an elimination-rehydroboration reaction. Deuterium-labeling experiments were performed and the reaction mechanism is discussed.

Original language	English
Pages (from-to)	2632-2636
Number of pages	5
Journal	Journal of the American Chemical Society
Volume	91
Issue number	10
DOIs	https://doi.org/10.1021/ja01038a039
State	Published - May 1969
Externally published	Yes

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title = "Hydroboration of Enol Acetates",

abstract = "The directive effect of an acetoxy substituent in the hydroboration of olefins was examined. Cyclohexenyl acetate and 2-cholesten-3-ol acetate (7) yielded the expected diols, but in addition a considerable amount of monols was obtained. Cyclopentenyl acetate and 2-cholesten-3-ol benzoate gave only monols and none of the expected diol products. ∆16-17-Acetoxy steroid 6 gave a trans diol on hydroboration. The yield of monol from cyclohexenyl acetate was raised with increasing temperature and increasing amount of diborane. Pyridine borane-aluminum chloride gave solely cyclohexanol. It was shown that the monol derived from 7 did not result from an elimination-rehydroboration reaction. Deuterium-labeling experiments were performed and the reaction mechanism is discussed.",

author = "Alfred Hassner and Barnett, {Ronald E.} and P. Catsoulacos and Wilen, {S. H.}",

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T1 - Hydroboration of Enol Acetates

AU - Hassner, Alfred

AU - Barnett, Ronald E.

AU - Catsoulacos, P.

AU - Wilen, S. H.

PY - 1969/5

Y1 - 1969/5

N2 - The directive effect of an acetoxy substituent in the hydroboration of olefins was examined. Cyclohexenyl acetate and 2-cholesten-3-ol acetate (7) yielded the expected diols, but in addition a considerable amount of monols was obtained. Cyclopentenyl acetate and 2-cholesten-3-ol benzoate gave only monols and none of the expected diol products. ∆16-17-Acetoxy steroid 6 gave a trans diol on hydroboration. The yield of monol from cyclohexenyl acetate was raised with increasing temperature and increasing amount of diborane. Pyridine borane-aluminum chloride gave solely cyclohexanol. It was shown that the monol derived from 7 did not result from an elimination-rehydroboration reaction. Deuterium-labeling experiments were performed and the reaction mechanism is discussed.

AB - The directive effect of an acetoxy substituent in the hydroboration of olefins was examined. Cyclohexenyl acetate and 2-cholesten-3-ol acetate (7) yielded the expected diols, but in addition a considerable amount of monols was obtained. Cyclopentenyl acetate and 2-cholesten-3-ol benzoate gave only monols and none of the expected diol products. ∆16-17-Acetoxy steroid 6 gave a trans diol on hydroboration. The yield of monol from cyclohexenyl acetate was raised with increasing temperature and increasing amount of diborane. Pyridine borane-aluminum chloride gave solely cyclohexanol. It was shown that the monol derived from 7 did not result from an elimination-rehydroboration reaction. Deuterium-labeling experiments were performed and the reaction mechanism is discussed.

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Hydroboration of Enol Acetates

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