Ladder Structure of a Lithium Organyl:  Synthesis and Crystal Structure of a Mixed Aggregate of n-BuLi and an (Aminomethyl)(lithiomethyl)silane

Abstract

BuLi and the (aminomethyl)-(lithiomethyl)silane 3 shows a higher reactivity than the separate compounds. A single-crystal X-ray structure of the mixed aggregate between n-BuLi and the (lithiomethyl)silane 2 ) establishes a ladder structure of the lithiumorganyl in the solid state.

Isolation of reactive intermediates in deprotonation reactions with zinc alkyls

“…Generally, the a-lithiation of silanes with alkyl lithium reagents is facilitated by the incorporation of more than one additional coordination site, which promote the deaggregation of the alkyl lithium species. 17 This behaviour is not observed with the model system presented herein, since this deaggregation process is not necessary for Et 2 Zn and the coordination sphere of the zinc atom is saturated with two additional donor atoms. This reduced reactivity due to saturation of coordination sites at the metal centre is also observed for metalation reactions performed in donor solvents.…”

Hetero‐Aggregate Compounds of Aryl and Alkyl Lithium Reagents: A Structurally Intriguing Aspect of Organolithium Chemistry

“…[1c-g, 10f, 10k, [11][12][13][14] This situation is somewhat surprising since the formation of an ArLi typically either involves Li-X or Li-H exchange reactions. In Li-H exchange, the amount of ArLi formed gradually increases as the lithiating agent, such as nBuLi, is consumed.…”

“…One hetero-aggregate 4 has been specifically identified as an essential intermediate which induces the enantioselective addition of 2 to 3; aggregate 4 is only formed after the addition of [R*OLi] to lithium cyclopropylacetylide and a suitable induction period. [4,8,10] Much less studied (or discussed) are the structures of mixed aryl or alkyl lithium hetero-aggregates, that is, [11][12][13][14] This situation is somewhat surprising since the formation of an ArLi typically either involves Li-X or Li-H exchange reactions. In Li-H exchange, the amount of ArLi formed gradually increases as the lithiating agent, such as nBuLi, is consumed.…”

Solid-state and solution structures of hetero-aggregates formed between nBuLi and NCN pincer aryl lithium

“…[33][34][35][36][37] As there is the potential to elucidate meaningful structure-activity relationships, the solution and solid state structures of organolithium heteroaggregates are topics of current interest. [41][42][43][44][45][46][47][48][49][50][51][52] One issue often ignored is the potential impact of these aggregates on the synthesis of organolithium reagents and their subsequent reactivity, as these are often generated and employed in situ. [53][54][55] Our research group has performed a number of investigations on the organolithium chemistry of 2,6-bis-[(dialkylamino)methyl]aryl-1-lithium species (the potentially terdentate NCN 'pincers') 56-59 1 and have reported some of their hetero-aggregate chemistry with nBuLi.…”