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Abstract Catalytic asymmetric α-alkylation of carbonyl compounds represents a long-standing challenge in synthetic organic chemistry. Herein, we advance a dual biocatalytic platform for the efficient asymmetric alkylation of α-keto acids. First, guided by our recently obtained crystal structures, we develop SgvMVAVas a general biocatalyst for the enantioselective methylation, ethylation, allylation and propargylation of a range of α-keto acids with total turnover numbers (TTNs) up to 4,600. Second, we mine a family of bacterial HMTs fromPseudomonasspecies sharing less than 50% sequence identities with known HMTs and evaluated their activities in SAM regeneration. Our best performing HMT fromP. aeruginosa,PaHMT, displays the highest SAM regeneration efficiencies (TTN up to 7,700) among HMTs characterized to date. Together, the synergistic use of SgvMVAVandPaHMT affords a fully biocatalytic protocol for asymmetric methylation featuring a record turnover efficiency, providing a solution to the notorious problem of asymmetric alkylation.
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Graphene oxide catalyzed ketone α-alkylation with alkenes: enhancement of graphene oxide activity by hydrogen bonding
Direct α-alkylation of carbonyl compounds represents a fundamental bond forming transformation in organic synthesis. We report the first ketone-alkylation using olefins and alcohols as simple alkylating agents catalyzed by graphene oxide. Extensive studies of the graphene surface suggest a pathway involving dual activation of both coupling partners. Notably, we show that polar functional groups have a stabilizing effect on the GO surface, which results in a net enhancement of the catalytic activity. The method represents the first alkylation of carbonyl compounds using graphenes, which opens the door for the development of an array of protocols for ketone functionalization employing common carbonyl building blocks and readily available graphenes.
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- Award ID(s):
- 1650766
- PAR ID:
- 10146144
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 55
- Issue:
- 37
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 5379 to 5382
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c9cc02578b
