Ni-catalyzed deaminative cross-electrophile coupling of Katritzky salts with halides via C─N bond activation

Abstract

The reductive cross-coupling of sp3-hybridized carbon centers represents great synthetic values and insurmountable challenges. In this work, we report a nickel-catalyzed deaminative cross-electrophile coupling reaction to construct C(sp)─C(sp3), C(sp2)─C(sp3), and C(sp3)─C(sp3) bonds. A wide range of coupling partners including aryl iodides, bromoalkynes, or alkyl bromides are stitched with alkylpyridinium salts that derived from the corresponding primary amines. The advantages of this methodology are showcased in the two-step synthesis of the key lactonic moiety of (+)-compactin and (+)-mevinolin. The one-pot procedure without isolation of alkylpyridinium tetrafluoroborate salt is also proven to be successful. This cross-coupling strategy of two electrophiles provides a highly valuable vista for the convenient installation of alkyl substituents and late functionalizations of sp3 carbons.

Manganese-mediated reductive functionalization of activated aliphatic acids and primary amines

“…Diheteroaryl disulfide was applicable as well (30). Interestingly, the use of dialkyl disulfides in this reaction also delivered the desired products (31)(32)(33)(34)(35), although the yields are not satisfactory. A notable feature is the survival of halogens (6-8, 12, 16-22, 24, 25, 39-41) and terminal alkene (33).…”

“…For this purpose, one feasible way is to activate the carboxylic acids and alkyl primary amines to the corresponding redox-active esters (RAE) and Katritzky's N-alkylpyridinium salts, respectively 16,17 . Previous studies demonstrated that both RAE [18][19][20][21][22][23][24][25][26][27][28] and Katritzky's salts [29][30][31][32][33][34][35][36][37] are predisposed to accept an electron from low-valent transition metals or organic Lewis bases under photocatalytic reaction conditions, thereby acting as precursors to the corresponding alkyl radicals (Fig. 1b) [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] .…”

Pyridinium Salts as Redox‐Active Functional Group Transfer Reagents

“…Han and co-workers were able to extend the scope of reductive alkyl pyridinium cross-coupling reactions to include bromoalkynes and alkyl bromides in addition to aryl iodides. [38] This wide range of coupling partners was enabled through the use of aterpyridine ligand in conjunction with Zn as the stoichiometric reductant at elevated temperatures.…”

Pyridiniumsalze als redoxaktive Reagenzien zur Übertragung funktioneller Gruppen

“…Han und Mitarbeiter konnten den Anwendungsbereich der reduktiven Alkylpyridinium‐Kreuzkupplungen neben Aryliodiden auch auf Bromalkine und Alkylbromide erweitern . Diese breite Palette von Kupplungspartnern wurde durch die Verwendung eines Terpyridinliganden in Verbindung mit Zn als stöchiometrischem Reduktionsmittel bei erhöhten Temperaturen ermöglicht.…”