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Title
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Directed C-H functionalization reactions with a picolinamide directing group : Ni-catalyzed cleavage and byproduct recycling
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Author
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Abstract
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| An efficient strategy for the cleavage of the picolinamide directing group (DG) and recycling of the by-product generated has been developed. In this protocol, picolinamides were first Boc activated into tertiary N-Boc-N-substituted picolinamides. These were then cleaved via a Ni-catalyzed esterification reaction with EtOH to give valuable N-Boc protected amines. Ni(cod)2was used as a catalyst without any ligands or base additives. The by-product, ethyl 2-picolinate can be used to install the picolinamide DG in a direct or indirect manner on amines. The protocol exhibits a broad functional group tolerance and high yields. To demonstrate the utility of this approach, it was applied on a number of selected examples from the recent C−H functionalization literature featuring 2-picolinamide as a DG. |
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Language
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English
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Source (journal)
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The journal of organic chemistry. - Washington, D.C., 1936, currens
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Publication
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Washington, D.C.
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2019
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ISSN
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0022-3263
[print]
1520-6904
[online]
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DOI
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10.1021/ACS.JOC.9B02299
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Volume/pages
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84
:20
(2019)
, p. 13112-13123
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ISI
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000492118100038
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Full text (Publisher's DOI)
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Full text (open access)
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