92040-47-6Relevant articles and documents
Thioether-Directed NiH-Catalyzed Remote γ-C(sp3)-H Hydroamidation of Alkenes by 1,4,2-Dioxazol-5-ones
Chen, Qishu,Du, Bingnan,Ouyang, Yuxin,Yu, Wing-Yiu
supporting information, p. 14962 - 14968 (2021/09/29)
A NiH-catalyzed thioether-directed cyclometalation strategy is developed to enable remote methylene C-H bond amidation of unactivated alkenes. Due to the preference for five-membered nickelacycle formation, the chain-walking isomerization initiated by the NiH insertion to an alkene can be terminated at the γ-methylene site remote from the alkene moiety. By employing 2,9-dibutyl-1,10-phenanthroline as the ligand and dioxazolones as the reagent, the amidation occurs at the γ-C(sp3)-H bonds to afford the amide products in up to 90% yield (>40 examples) with remarkable regioselectivity (up to 24:1 rr).
Exploratory synthetic studies of the α-methoxylation of amides via cuprous ion-promoted decomposition of o-diazobenzamides
Han, Gyoonhee,LaPorte, Matthew G.,McIntosh, Mathias C.,Weinreb, Steven M.,Parvez, Masood
, p. 9483 - 9493 (2007/10/03)
A convenient nonelectrochemical amide oxidation method has been developed. The process involves a cuprous ion-promoted decomposition of o-diazobenzamides like 4, generated in situ from the corresponding o-aminobenzamides, to give N-acyliminium ion intermediate 9 via a 1,5-H-atom transfer, followed by metal-catalyzed oxidation of the resulting α-amidyl radical. The transformation produces α-methoxybenzamides 15 in good yields. An attempt was made to apply this oxidation method to a total synthesis of the alkaloid (-)-anisomycin (16). Scalemic o-aminobenzamide pyrrolidine derivatives 18a/18b underwent oxidation to give α-methoxylated amide substrates 19a/19b, respectively, in good yields. However, alkylation of the N-acyliminium intermediate 20 with (p-methoxybenzyl)magnesium chloride gave the undesired anti-compounds 22a/22b as the major products. The amide oxidation exhibits good regioselectivity with many unsymmetrical 2-substituted piperidine and pyrrolidine systems. In general, it appears that the larger the C-2 substituent, the greater the methylene/methine H-atom abstraction ratio. A mechanistic rationale for this selectivity is suggested based upon amide rotamer populations. An extension of this methodology can be used to conduct two sequential amide oxidations using readily prepared 2-amino-6-nitrobenzamides such as 68 and 69.
