02067nas a2200193   4500008004100000022001400041245014200055210006900197260000800266300001600274490000700290520135000297100001901647700002101666700001701687700002401704700001901728856012601747       2024                        eng d  a2041-652000aUncovering diverse reactivity of NHCs withdiazoalkane: C-H activation, C=C bond formation,and access to N-heterocyclic methylenehydrazine0 aUncovering diverse reactivity of NHCs withdiazoalkane CH activat  cNOV  a18387-183940 v153 a<p>
	N-heterocyclic carbenes (NHCs) have attracted significant attention due to their strong sigma-donating capabilities, as well as their transition-metal-like reactivity towards small molecules. However, their interaction with diazoalkanes remains understudied. In this manuscript, we explore the reactivity of a series of stable carbenes, encompassing a wide range of electronic properties, with Me3SiCHN2. 5-SIPr activates the C-H bond of Me3SiCHN2, resulting in the formation of a novel diazo derivative (1), while carbenes such as 5-IPr, 6-SIPr, and diamido carbene yield N-heterocyclic methylenehydrazine derivatives (3, 4, and 8). The reaction of Me3SiCHN2 with 5-ItBu unexpectedly leads to the formation of a triazole ring linked with the imidazole moiety via a CC double bond (6) alongside the azine product (7). Substituting the diazoalkane with diazoester consistently yields azine derivatives (9-12 and 14). Only in the case of 5-ItBu, an imidazolium salt with tetrazenide anion (13) was obtained as a side product. The reaction of 4 with HCl resulted in the desilylprotonation to form a salt, 5a, which undergoes deprotonation upon using bases such as Et3N and KHMDS to form N-heterocyclic methylene hydrazine, 5. Theoretical calculations have been conducted to elucidate the diverse mechanisms underlying product formation.</p>
1 aBalayan, Kajal1 aSharma, Himanshu1 aVanka, Kumar1 aGonnade, Rajesh, G.1 aSen, Sakya, S.  uhttps://library.ncl.res.in/content/uncovering-diverse-reactivity-nhcs-withdiazoalkane-c-h-activation-cc-bond-formationand