Bis(lithiomethyl) Sulfide, An Unexpectedly Stable 1,3‐Dilithiated Synthetic Building Block

Abstract

Although extremely useful, only a few 1,3‐dilithiated organoelement compounds are known, because no suitable synthetic methods were available. Now bis(lithiomethyl) sulfide (2) has been prepared by double metal‐lithium exchange (transmetalation) from 1 and 3. At room temperature 2 is a colorless metastable powder.

Tris- and Tetrakis(lithiomethyl)silanes: An Easy Access to New Building Blocks for Organosilicon Compounds

“…Preparation of Tris(lithiomethyl)silane and Tetrakis(lithiomethyl)silane Reagents. The tris(phenylthiomethyl)silanes 3a-d and tetrakis(phenylthiomethyl)silane (7) used for reductive cleavage were prepared by reaction of (phenylthiomethyl)lithium with the corresponding chlorosilanes 2a-d and 6 (Scheme 2). (Phenylthiomethyl)lithium was synthesized by two methods: reaction of thioanisole, 1,4-diazabicyclo[2,2,2]octane (DABCO), and n-BuLi in THF 11 and reaction of thioanisole and n-BuLi in diethyl ether.…”

“…The tris(phenylthiomethyl)silanes 3a-d were isolated by Kugelrohr distillation (3a-c) or by crystallization (3a, 3d) in 53%-60% yield. Tetrakis(phenylthiomethyl)silane (7) was isolated by crystallization in 52% yield.…”

“…As a part of our systematic studies ,, on the structural unit “ − CR 2 − M − CR 2 − ” [M = element of groups 14−16, partly with substituents (R = H, alkyl, aryl)], we have investigated the synthesis of bis(lithiomethyl)silanes with the structural unit “Li CH 2 − SiR 2 − CH 2 Li” (M = SiR 2 ). The silicon atom stabilizes the lithio substituent in the α-position and prevents the β-elimination reaction…”

“…Also, their decomposition by β-elimination of LiH (e.g., 1,3-dilithiopropane decomposes at -60 °C to allyllithium 6 ) prevented their preparation. 1 As a part of our systematic studies 4,7,8 on the structural unit "-CR 2 -M-CR 2 -" [M ) element of groups 14-16, partly with substituents (R ) H, alkyl, aryl)], we have investigated the synthesis of bis(lithiomethyl)silanes with the structural unit "LiCH 2 -SiR 2 -CH 2 Li" (M ) SiR 2 ). The silicon atom stabilizes the lithio substituent in the R-position and prevents the β-elimination reaction.…”

Metal Complexes of Scorpionate-Like Polyimido Sulphur Phosphanyl Ligands

“…[S(CH 2 Li) 2 ] can be synthesised by tellurium-lithium exchange but is highly explosive. [144] Strohmann et al reported in 2010 the double deprotonation of dimethylphenylphosphine borane with tBuLi and (R,R)-TMCDA. [145] This reaction readily proceeds at -30 °C which is due to stabilizing Li-H interactions with the borane that lower the barrier for the second deprotonation to only 92 kJ/mol.…”