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Photoredox mediated nickel catalyzed C(sp³)-H thiocarbonylation of ethers.

ABSTRACT: The first direct C(sp³)-H thiocarbonylation reaction is achieved by visible light photoredox/Ni dual catalysis. The thioester group of thiobenzoate is transferred to the ?-oxy carbon of various cyclic/acyclic ethers, which is the opposite to the commonly expected chemical reactivity involving acyl group transfer via the weaker C(acyl)-S activation. Through mechanistic studies, we proposed that the reaction is initiated by photocatalytic reduction and fragmentation of the thioester into an acyl radical and a thiolate. A nickel complex binds to the thiolate and induces the decarbonylation of the acyl radical to form an aryl radical, which abstracts hydrogen from the ?-oxy carbon of the ether. The resulting ?-oxy C(sp³) centered radical re-binds to the (RS)(CO)Ni complex, which undergoes CO migratory insertion and reductive elimination to give the desired thioester product.

SUBMITTER: Kang B

PROVIDER: S-EPMC5627187 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Photoredox mediated nickel catalyzed C(sp3)-H thiocarbonylation of ethers.

Kang Byungjoon B Hong Soon Hyeok SH

Chemical science 20170724 9

The first direct C(sp3)-H thiocarbonylation reaction is achieved by visible light photoredox/Ni dual catalysis. The thioester group of thiobenzoate is transferred to the α-oxy carbon of various cyclic/acyclic ethers, which is the opposite to the commonly expected chemical reactivity involving acyl group transfer via the weaker C(acyl)-S activation. Through mechanistic studies, we proposed that the reaction is initiated by photocatalytic reduction and fragmentation of the thioes ...[more]

PMID: 28989688

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