Practical Catalytic Cleavage of C(sp³)−C(sp³) Bonds in Amines

Abstract

The selective cleavage of thermodynamically stable C(sp3)−C(sp3) single bonds is rare compared to their ubiquitous formation. Herein, we describe a general methodology for such transformations using homogeneous copper‐based catalysts in the presence of air. The utility of this novel methodology is demonstrated for Cα−Cβ bond scission in >70 amines with excellent functional group tolerance. This transformation establishes tertiary amines as a general synthon for amides and provides valuable possibilities for their scalable functionalization in, for example, natural products and bioactive molecules.

Deconstructive Oxygenation of Unstrained Cycloalkanamines

“…When the reaction was conducted under Ar, the product e1 was remarkably reduced to 16 % yield (entry 7). Solvent screening results showed that DMA was a better choice than CH 3 CN, dichloroethane (DCE), toluene, and methanol (entries [8][9][10][11].…”

“…Cycloalkyliminyl and cycloalkylaminyl radical involved ring-opening reactions have attracted much attention in recent years. [7][8][9] For example, the groups of Zard, [7a,c] Leonori, [7f] Xiao, [7e] and Guo [7g] have developed iminyl-radical-mediated ring-opening of strained rings by using either oxime esters or ethers as the substrates (Scheme 1 b). Meanwhile, the groups of Zheng [8a-c] and Waser [8e] have independently reported ring-opening reconstruction and functionalization of strained cyclopropylamines and cyclobutylamines.…”

Copper loaded nitrogen-rich mesoporous carbon nitride as a highly efficient photocatalyst for selective oxidative cleavage of C(sp3)–C(sp3) bonds at room temperature under visible light

“…In the reported examples on the cleavage of C–C bonds in amines, the single electron oxidation of amines was believed to play a vital role from both transformative and mechanistic aspects in these processes. 13–15 To the best of our knowledge, for the target reaction, no heterogeneous nanometric semiconductor photocatalysts have been employed. Inspired by our previous work, 45 we commenced an efficient protocol for the selective cleavage of C(sp 3 )–C(sp 3 ) bonds within N -phenylmorpholines applying the heterogeneous Cu/PCN catalyst under visible light and aerobic conditions.…”

“…From these results, we supposed that prior to the oxidative cleavage process, the C(sp 3 )–C(sp 3 ) bond undergoes dehydrogenation to form a more labile C(sp 2 )C(sp 2 ) bond. 14,58…”

“…Recently, some homogeneous transition-metal catalysis systems have been developed to break the C–C bonds in amines. 12–20 However, most of the reactions suffered from stoichiometric oxidants, high temperature or high cost of transition-metal complexes. Thus, development of an environmentally friendly and sustainable methodology for the C–C bond cleavage in amines is still under investigation.…”