[1,5]-Brook rearrangement: an overlooked but valuable silyl migration to synthesize configurationally defined vinylsilane. The unique steric and electronic effects of geminal bis(silane).
نویسندگان
چکیده
An unusual [1,5]-Brook rearrangement of the lithium alkoxide of geminal bis(silyl) homoallylic alcohol is described. The unique steric and electronic effects of geminal bis(silane) were found to be crucial for promoting this long-range silyl migration, as well as for facilitating the subsequent γ/Z-selective addition of silyl allyllithium with carbonyl compounds to synthesize diverse configurationally defined Z-vinylsilanes.
منابع مشابه
The [1,5]-Brook rearrangement: an initial application in anion relay chemistry.
The [1,5]-Brook rearrangement proceeds efficiently in a series of hydroxyl dithiane substrates with sodium and potassium bases; less effective are lithium bases. That the mode of silyl migration is intramolecular was demonstrated by a crossover experiment. Finally, the tricomponent anion relay chemistry (ARC) coupling tactic was demonstrated employing the [1,5]-Brook rearrangement.
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متن کاملA radical thia-Brook rearrangement.
Geminal mercapto trialkyl- and trialkoxy-silanes undergo an efficient radical chain rearrangement, whereby the silyl group migrates from carbon to sulfur; the starting materials are readily obtained by exploiting the peroxide initiated radical addition of dithiocarbonates (xanthates) to trialkyl- or trialkoxy-vinylsilanes.
متن کاملUnexpected syn hydride migration in the non-aldol aldol reaction.
[structure: see text] Non-aldol aldol rearrangement of the epoxy silyl ether 13b afforded the expected anti methyl ketone 14, while the diastereomeric epoxy silyl ether 13a afforded the syn methyl ketone 8b via an unprecedented syn hydride migration. Calculations suggest that this unusual reaction proceeds via the carbocation, which cannot easily rotate due to steric hindrance.
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ورودعنوان ژورنال:
- Chemical communications
دوره 49 79 شماره
صفحات -
تاریخ انتشار 2013