RESUMEN
A straightforward gram-scale preparation of cyclohexa-1,4-diene-based hydrogen cyanide (HCN) surrogates is reported. These are bench-stable but formally release HCN and rearomatize when treated with Lewis acids. For BCl3 , the formation of the isocyanide adduct [(CN)BCl3 ]- and the corresponding Wheland complex was verified by mass spectrometry. In the presence of 1,1-di- and trisubstituted alkenes, transfer of HCN from the surrogate to the C-C double bond occurs, affording highly substituted nitriles with Markovnikov selectivity. The success of this transfer hydrocyanation depends on the Lewis acid employed; catalytic amounts of BCl3 and (C6 F5 )2 BCl are shown to be effective while B(C6 F5 )3 and BF3 â OEt2 are not.
RESUMEN
A one-pot reaction that directly converts dihydrosilanes into silyl ethers of tertiary silanes is reported. Under palladium catalysis, one Si-H bond of the dihydrosilane formally engages in C(sp3 )-Si bond formation with a vinyl iodide while the other Si-H bond is transformed into a silyl iodide that undergoes facile alcoholysis with an alcohol. The C-C double bond is reduced in that process. This three-component reaction provides in a single synthetic operation an access to silyl ethers of functionalized and hindered alcohols. Several of those would otherwise be difficult to make but the intermediacy of a highly reactive silyl iodide even allows for tert-butanol to react at room temperature.
RESUMEN
The cyclohexa-1,3-diene motif is introduced as an equally effective alternative to the cyclohexa-1,4-diene platform in B(C6F5)3-catalysed transfer processes. The transfer hydrogenation of alkenes is realised with α-terpinene and the related transfer hydrosilylation is achieved with 5-trimethylsilyl-substituted cyclohexa-1,3-diene. Both yields and substrate scope are comparable with the prior systems.