Dioxane−Monochloroborane:  A New and Highly Reactive Hydroborating Reagent with Exceptional Properties

Dioxane−monochloroborane was prepared by the reaction of dioxane and dioxane−BCl3 with diborane or NaBH4 in 98% purity. The adduct thus obtained is a liquid, 6.2 M in BH2Cl, stable indefinitely at either 0 or 25 °C. The adduct hydroborates simple unhindered olefins to the corresponding dialkylchloro...

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Bibliographic Details
Published inOrganic letters Vol. 1; no. 2; pp. 315 - 318
Main Authors Kanth, Josyula V. B, Brown, Herbert C
Format Journal Article
LanguageEnglish
Published WASHINGTON American Chemical Society 29.07.1999
Amer Chemical Soc
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
KETONES
CHIRAL REDUCING AGENT
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Summary:Dioxane−monochloroborane was prepared by the reaction of dioxane and dioxane−BCl3 with diborane or NaBH4 in 98% purity. The adduct thus obtained is a liquid, 6.2 M in BH2Cl, stable indefinitely at either 0 or 25 °C. The adduct hydroborates simple unhindered olefins to the corresponding dialkylchloroboranes within 0.5 h, while moderately hindered olefins take 1−4 h at room temperature. Hindered tetrasubstituted olefins rapidly hydroborate to the monoalkylchloroborane stage with further hydroboration slow. Regioselectivity studies of representative olefins reveal that this new reagent possesses selectivities similar to those from the monochloroborane−diethyl ether adduct. Consequently, dioxane−monochloroborane can readily substitute for the older hydroborating agents, BH3:THF and BH3:DMS.
ISSN:1523-7060
1523-7052
DOI:10.1021/ol990639b