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Meta-selective borylation: Meta-selective C–H borylation is an important synthetic transformation, which was discovered in 2002 by Smith III from Michigan State University, USA. However, this meta borylation was completely sterically directed and was limited to only 1,3-disubstituted benzenes.
The Miyaura borylation has shown to work for: Alkyl halides, [ 2 ] aryl halides, [ 1 ] [ 3 ] [ 4 ] aryl halides using tetrahydroxydiboron , [ 5 ] aryl halides using bis-boronic acid, [ 6 ] aryl triflates , [ 7 ] aryl mesylates , [ 8 ] vinyl halides, [ 9 ] vinyl halides of α,β-unsaturated carbonyl compounds, [ 10 ] and vinyl triflates.
Above: Upon reduction of the arylboron dichloride, a borylene is liberated. This intermediate adds into a C-C bond in the mesityl group. [11] Below: Reduction of an dichloroaminoborane with Na/K yields a transient aminoborylene.
The process flow diagram below depicts a typical semi-regenerative catalytic reforming unit. Schematic diagram of a typical semi-regenerative catalytic reformer unit in a petroleum refinery. The liquid feed (at the bottom left in the diagram) is pumped up to the reaction pressure (5–45 atm) and is joined by a stream of hydrogen-rich recycle gas.
The general structure of a boronic acid, where R is a substituent.. A boronic acid is an organic compound related to boric acid (B(OH) 3) in which one of the three hydroxyl groups (−OH) is replaced by an alkyl or aryl group (represented by R in the general formula R−B(OH) 2). [1]
Pinacolborane is used in borylation, a form of C-H activation. [8] [9] Dehydrogenation of pinacolborane affords dipinacolatodiborane (B 2 pin 2): [10] 2 ...
The mechanism consists of five steps: Base catalyzed carbonyl enolization of the α-isocyanide.; Michael-type addition between the α-isocyanide carbonyl enolate and the nitroalkene.
The hydroxy acid first reacts with the 2,2'-Dipyridyldisulfide to form the corresponding 2-pyridinethiol ester, and after a proton transfer, the alkoxide attacks the carbonyl carbon, forming a tetrahedral transition state, before resolving back to the desired lactone and 2-pyridinethione.