Functionalizing Glycine Derivatives by Direct CC Bond Formation

Catalytic Oxidation of C(sp3)H Bonds Induced by a Radical Cation Salt: Construction of 1,4‐Dihydropyridines Using a Fragment‐Reassembly Strategy

“…[7] This method represented a novel approach to CDCs (cross dehydrogenative coupling reactions), avoiding using excess quantities of the oxidants (such as DDQ, TEMPO, oxoammonium, and peroxides). [8] This methodology was also applied to the catalytic aromatization of 1,4-dihydropyridines. [9] When other nucleophiles (indoles, for example) were used to trap the in situ generated radical intermediate, C À N cleavage occurred, producing the corresponding aniline by-products.…”

Beyond Traditional Cross Couplings: The Scope of the Cross Dehydrogenative Coupling Reaction

“…[22] It was found that upon switching the protecting group from an amide to a para-methoxy phenyl (PMP) group, the CDC with phenyl acetylene could be accomplished at room temperature under the CuBr/TBHP system previously reported. [12] When two sites for CDC, that is, two different glycine residues, were available in the coupling partner then the reaction selectively occurred at the N-protected glycine terminus and not the nitrogen a-to the amide bond.…”

“…[22] Initially the reaction was met without success when the reaction was carried out under the previously reported conditions for CÀC bond formation between isoquinoline and alkyl malonates, namely CuBr and TBHP. [19] However, when other copper sources were investigated it was found that two equivalents of copper(II) acetate gave small amounts of the coupled product.…”

Synthesis of α‐Ethynyl Glycines

“…Li's group reported synthesis of α-alkynyl glycines 33a by the C-H bond functionalization of N-PMP-protected glycine amides 32a using a cross-dehydrogenative coupling reaction with aromatic alkynes (Scheme 5). [29] In this case, the reaction conditions involved CuBr as the catalyst and tert-butyl hydroperoxide (TBHP) as an oxidant. According to the proposed mechanism, Cu I has a dual role in this reaction.…”