16 research outputs found
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Erratum: Development of a generic activation mode: nucleophilic a-substitution of ketones via oxy-allyl cations
Erratum.Oxy-allyl cations have been known as transient electrophilic species since they were first proposed as intermediates in the Favorskii rearrangement in 1894. Since that time, they also have been used as a mode of activation for [4 + 3] cycloadditions in a variety of natural product syntheses. In this manuscript, we describe a method for the interception of oxy-allyl cations with a diverse range of common nucleophiles, thereby demonstrating the value of this intermediate as a generic mode of activation. This simple, mild, room temperature protocol allows for the formation of a variety of high value carbon–carbon and carbon–heteroatom bonds that are readily incorporated within a series of cyclic and acyclic ketone systems. Initial efforts into the development of an enantioselective catalytic variant are also described
Recommended from our members
Development of a generic activation mode: nucleophilic α-substitution of ketones via oxy-allyl cations
Oxy-allyl cations have been known as transient electrophilic species since they were first proposed as intermediates in the Favorskii rearrangement in 1894. Since that time, they also have been used as a mode of activation for [4 + 3] cycloadditions in a variety of natural product syntheses. In this manuscript, we describe a method for the interception of oxy-allyl cations with a diverse range of common nucleophiles, thereby demonstrating the value of this intermediate as a generic mode of activation. This simple, mild, room temperature protocol allows for the formation of a variety of high value carbon–carbon and carbon–heteroatom bonds that are readily incorporated within a series of cyclic and acyclic ketone systems. Initial efforts into the development of an enantioselective catalytic variant are also described
Development of a generic activation mode: nucleophilic a-substitution of ketones via oxy-allyl cations â€
Oxy-allyl cations have been known as transient electrophilic species since they were first proposed as intermediates in the Favorskii rearrangement in 1894. Since that time, they also have been used as a mode of activation for [4 + 3] cycloadditions in a variety of natural product syntheses. In this manuscript, we describe a method for the interception of oxy-allyl cations with a diverse range of common nucleophiles, thereby demonstrating the value of this intermediate as a generic mode of activation. This simple, mild, room temperature protocol allows for the formation of a variety of high value carbon-carbon and carbonheteroatom bonds that are readily incorporated within a series of cyclic and acyclic ketone systems. Initial efforts into the development of an enantioselective catalytic variant are also described
Oxy-Allyl Cation Catalysis: An Enantioselective Electrophilic Activation Mode
A generic
activation mode for asymmetric LUMO-lowering catalysis
has been developed using the long-established principles of oxy-allyl
cation chemistry. Here, the enantioselective conversion of racemic
α-tosyloxy ketones to optically enriched α-indolic carbonyls
has been accomplished using a new amino alcohol catalyst in the presence
of electron-rich indole nucleophiles. Kinetic studies reveal that
the rate-determining step in this S<sub>N</sub>1 pathway is the catalyst-mediated
α-tosyloxy ketone deprotonation step to form an enantiodiscriminant
oxy-allyl cation prior to the stereodefining nucleophilic addition
event
Oxy-Allyl Cation Catalysis: An Enantioselective Electrophilic Activation Mode
A generic
activation mode for asymmetric LUMO-lowering catalysis
has been developed using the long-established principles of oxy-allyl
cation chemistry. Here, the enantioselective conversion of racemic
α-tosyloxy ketones to optically enriched α-indolic carbonyls
has been accomplished using a new amino alcohol catalyst in the presence
of electron-rich indole nucleophiles. Kinetic studies reveal that
the rate-determining step in this S<sub>N</sub>1 pathway is the catalyst-mediated
α-tosyloxy ketone deprotonation step to form an enantiodiscriminant
oxy-allyl cation prior to the stereodefining nucleophilic addition
event