Three different product types from reactions of lithiated cyclic aminals with trivalent organometal chlorides

Abstract

The reaction of 2-lithio-1,3,5-trimethyl-1,3,5-triazacyclohexane with YCp(2)Cl leads to the formation of a donor-functionalised mono-anionic amide ligand, 1,3,5-trimethyl-2-(methylamidomethyl)-1,3,5-triazacyclohexane, bonded to the YCp(2) unit. The reaction involves a cleavage of the 1,3,5-triazacyclohexane ring and such a cleavage is also observed in the analogous reaction with (Me(3)C)(2)GaCl, where a MeN[double bond, length as m-dash]CH(-) fragment is formed. No such cleavage occurs in the reaction of the related dilithiated bicyclic bis(3-methyl-1,3-diazacyclohex-1-yl)methane with YCpCl(2).3thf, which affords a mixed lithium-yttrium organyl.

Silylation products of cyclic tri-aminal carbanions and their lithiation

“…The preparative yields were always moderate (2 69%, 3 78%, 4 69%). Compounds 2 and 3 were characterised by elemental analyses and NMR spectroscopy of the nuclei 1 H, 13 C and 29 Si. As most of these data deserve no detailed comments, we refer to the experimental part.…”

“…We reacted 5 with n-butyl lithium at -78 • C in hexane and obtained a product, metallated at the silicon bound methyl group: [{MeN(CH 2 NMe) 2 CH}SiMe(CH 2 Li)] 2 (8) (Scheme 3). Compound 8 was characterised by 1 H, 7 Li, 13 C and 29 Si NMR spectroscopy in C 6 D 6 solution.…”

“…The 7 Li NMR spectrum contains a resonance at 1.2 ppm. A 13 C NM resonance at -2.8 ppm corresponds to the carbanionic function SiCH 2 Li, while a signal at -1.1 ppm represents the Si-bound methyl group and one at 77.5 ppm, the ring carbon atom attached to silicon (SiCHN 2 ). The methylene NCH 2 N units give a signal at 79.3 ppm.…”

“…Bulkily substituted substrates lead to decomposition of 1 into MeN CH 2 and MeN CHLi fragments (TMTAC itself is a trimer of MeNCH 2 ) and these fragments are then found included in the products. 13 Cp 2 YCl for instance reacts with RLi to give the complex Cp 2 Y[h 4 (RCH 2 NMe)], with a new tetrapodal ligand and this monoanionic ligand is formed in one step (showing MeN CH 2 reactivity). t-Bu 2 GaCl reacts with 1 to give cyclo-[t-Bu 2 GaCH NMe] 2 (showing MeN CHLi reactivity).…”

Carbon‐metalated triazines and tetrazines: Synthesis and reactivity

“…Thus, combining lithiotriazine 169 with di-tert-butyl gallium(III) monochloride furnished the derivative 173 of a formal MeN CH − anion (Scheme 37). [54,55] Even more unexpectedly, when 169 was allowed to react with di-cyclopentadienyl yttrium chloride, the organometallic complex of a new type 172 was isolated (Scheme 37).…”