Alkali metal and magnesium enamides from metallation of the alkyl ligands [(2-Pyr)(SiMe3)CH2] and [6-Me-(2-Pyr)(SiMe3)CH2]: a solid state and ab initio study†

Calcium‐Mediated Dearomatization, CH Bond Activation, and Allylation of Alkylated and Benzannulated Pyridine Derivatives

“…The mesomerism of picolyl anions has been described previously and aza-allyl coordination by a doubly-activated b-diketiminato ligand to calcium has been discussed. [28,29] Figure 1 depicts a formally seven-coordinate calcium center. The bond lengths of 2.846(3) (Ca1-C6) and 2.813(3) (Ca1-C13) lie in the range of calcium-carbon bonds observed for the triglyme adduct of bisA C H T U N G T R E N N U N G (h 3 -allyl)calcium and exclude s-bound carbanionic ligands.…”

Novel Multidentate Sulfur–Nitrogen Ligands with Enhanced Complexation Properties

“…[1c, 26,28,29] They are also comparable to the bond lengths of 2.447(2)-2.566(2) in a structurally related dimeric sodium complex with 4,5-diazafluorene as a ligand. [28] Interestingly, the N3-Na1-N4 angle of 74.46(4)8 is more acute than the corresponding angle in the lithium complex (78.89(6)8).…”

Synthesis, Insertion Reactivity, and Transmetalation Reactions of the Lithium Complex [{2‐(6‐R‐Pyr)(Me3Si)}CHLi·OEt2]2 (R = H or Me)

“…[3b ] We have noted that all of the dimeric complexes of the type [(2-Pyr)(SiMe 3 )CHLi· (L)] 2 have the common feature of a central symmetric structure; however, to date there have been no examples of compounds with dimeric complexes with an asymmetric pattern.…”

“…[2] The silylated ligands are normally encountered in the azaallyl form commonly found in compounds like [(2-Pyr)(SiMe 3 )CHLi·(Et 2 O)] 2 , [3a] while the ligands with the enamide disposition are observed in complexes like [(2-Pyr)(SiMe 3 )CHLi·(tmeda)] 2 [3a] or [(2-Pyr)(SiMe 3 )CHLi·(sparteine)].…”

“…[7,8] Furthermore, a series of derived pyridyl-1-azaallyl low-valent group 14 compounds were described. [9,10] The synthesis of [MCl 2 {N(SiMe 3 )-C(Ph)C-(H)(C 9 H 6 N-2)}] (M = Hf and Zr) from the reaction of MCl 4 with the quinolyl-1-azaallyllithium complex [Li{N-(SiMe 3 )C(Ph)C(H)(C 9 H 6 N-2)}] 2 was reported previously, [11] as well as the synthesis of Pd complexes containing the 1-azaallyl ligand of [{[N(R)C(tBu)CH] 2 C 5 H 3 N-2,6}{Li 2 (tmen)}] and [{[N(R)C(Ph)CH] 2 C 5 H 3 N-2,6}{Li-(tmen) 2 }]. [12] In this paper, we report the synthesis of dimeric [{2-(6-R-Pyr)(Me 3 Si)}CHLi·OEt 2 ] 2 [R = H (1a) or Me (1b)], in which two lithium atoms have different bonding modes in an asymmetric pattern, and their insertion products to form the corresponding pyridyl-1-azaallyllithium complexes [{2- (4).…”