Lewis Acid Promoted, O-Selective, Nucleophilic Addition of Silyl Enol Ethers to NO bonds
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چکیده
منابع مشابه
Nickel-Catalyzed Reductive Conjugate Addition of Primary Alkyl Bromides to Enones To Form Silyl Enol Ethers
Conjugate addition of organometallic reagents to enones to form silyl enol ether products is a versatile method to difunctionalize activated olefins, but the organometallic reagents required can be limiting. The reductive cross-electrophile coupling of unhindered primary alkyl bromides with enones and chlorosilanes to form silyl enol ether products is catalyzed by a nickel-complexed ortho-bromi...
متن کاملSynthesis of 2-substituted 7-hydroxybenzofuran-4-carboxylates via addition of silyl enol ethers to o-benzoquinone esters.
Mukaiyama Michael addition of silyl enol ethers 13 to the 1,2-quinone-4-carboxylate 6 (formed in situ by oxidation of the catechol ester 8) afforded the 2-subsituted 7-hydroxybenzofuran-4-carboxylates 14 in fair to good yields. Alkyl and aryl systems work well, but highly electron-rich silyl enol ethers could not be used because of competing oxidation.
متن کاملFormal (3+3) cycloaddition of silyl enol ethers catalyzed by trifric imide: domino Michael addition-claisen condensation accompanied with isomerization of silyl enol ethers.
We describe here a Tf₂NH-catalyzed formal (3+3) cycloaddition of silyl enol ethers with acrylates as a new domino reaction. In the domino sequence, the catalyst activates Michael addition, deprotonation of the resulting silyloxonium cation and intramolecular Claisen condensation. It was found that reaction modes significantly depend on the reaction temperature. We also examined the mechanistic ...
متن کاملLewis acid-promoted oxidative addition of thioimidates to Pd0.
The isomeric S-methyldihydropyrrins 9-Z and 9-E exhibit markedly different behavior in Pd(0)-catalyzed cross-coupling reactions. Thioimidates 9-Z are readily converted to imines 10-Z employing Pd(0)/AlkZnI. Under identical conditions 9-E are inert. Oxidative addition to Pd(0) requires activation by Zn or other Lewis acids, which is sterically unfavorable with 9-E. Analogous results were obtaine...
متن کاملChemoselective silyl transfer in the Mukaiyama aldol reaction promoted by super silyl Lewis acid.
In the silyl Lewis acid-promoted Mukaiyama aldol reaction, the steric and electronic properties of the silyl group on the silyl Lewis acid influence the reaction mechanism and product distribution. When super silyl triflates such as (TMS)3SiOTf and (TES)3SiOTf are used as Lewis acids, the silyl group of the silyl enol ether chemoselectively transfers to the product. The mechanistic details have...
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ژورنال
عنوان ژورنال: Angewandte Chemie International Edition
سال: 2002
ISSN: 1433-7851,1521-3773
DOI: 10.1002/1521-3773(20020916)41:18<3313::aid-anie11113313>3.0.co;2-x