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6.1.38.1.2 Variation 2: With Monoalkylboranes

DOI: 10.1055/sos-SD-006-00903

Zaidlewicz, M.; Krzeminski, M.Science of Synthesis, (200561106.

Simple monoalkylboranes undergo ready disprotonation and must be generated and used within 12 hours.[‌85‌,‌86‌] In contrast, tert-butylborane is remarkably stable and no discernible changes in a tetrahydrofuran solution are evident for at least one week.[‌85‌] (1,1,2-Trimethylpropyl)borane (thexylborane) is a well studied reagent, useful for the hydroboration of alkenes and dienes.[‌1‌,‌87‌] It must be prepared freshly prior to use since it has a tendency to dehydroborate and isomerize. 2,4,4-Trimethylpent-3-ylborane (DIBborane, DibBH2) is a similar reagent readily available by hydroboration of a relatively inexpensive alkene.[‌88‌] Chiral terpenyl monoalkylboranes based on the pinane skeleton are useful for asymmetric hydroboration (see Scheme 20).[‌89‌‌95‌]

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References


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