Highly Enantioselective Michael Addition of Silyl Nitronates to α,β-Unsaturated Aldehydes Catalyzed by Designer Chiral Ammonium Bifluorides: Efficient Access to Optically Active γ-Nitro Aldehydes and Their Enol Silyl Ethers.
نویسندگان
چکیده
منابع مشابه
Iridium-catalyzed enantioselective allylation of silyl enol ethers derived from ketones and α,β-unsaturated ketones.
The unified Ir-catalyzed enantioselective allylic substitution reactions of silyl enol ethers derived from ketones and α,β-unsaturated ketones with branched, racemic allylic alcohols are described. This transformation is catalyzed by the Carreira system and proceeds without fluoride, and with high ee and b : l ratio. The synthetic utility of this method was illustrated by the concise enantiosel...
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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 کاملNickel-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 کاملHighly enantioselective addition of phenylethynylzinc to aldehydes catalyzed by chiral cyclopropane-based amino alcohols.
The enantioselective addition of phenylethynylzinc to aldehydes catalyzed by a series of cyclopropane-based amino alcohol ligands 7 was investigated. The reactions afforded chiral propargylic alcohols in high yields (up to 96%) and with excellent enantioselectivities (up to 98% ee) under mild conditions. Furthermore, studies on the structural relationship show that the matching of the chiral ce...
متن کاملHighly enantioselective conjugate addition of aldehydes to nitroolefins catalyzed by chiral bifunctional sulfamides.
Chiral bifunctional sulfamides were found to be highly efficient organocatalysts for the conjugate addition of aldehydes to nitroolefins in the presence of base additives.
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ژورنال
عنوان ژورنال: ChemInform
سال: 2003
ISSN: 0931-7597,1522-2667
DOI: 10.1002/chin.200345033