Vinyllithium

Vinyllithium is an organolithium compound with the formula LiC₂H₃. A colorless or white solid, it is encountered mainly as a solution in tetrahydrofuran (THF). It is a reagent in synthesis of organic compounds, especially for vinylations.^[1]

Vinyllithium

Identifiers
CAS Number	917-57-7
3D model (JSmol)	Interactive image
Beilstein Reference	3587231
ChEBI	CHEBI:51472
ChemSpider	10254403
ECHA InfoCard	100.011.844
EC Number	213-028-5
Gmelin Reference	723
PubChem CID	637931
CompTox Dashboard (EPA)	DTXSID10238670
InChI InChI=1S/C2H3.Li/c1-2;/h1H,2H2; Key: PGOLTJPQCISRTO-UHFFFAOYSA-N
SMILES [Li]C=C
Properties
Chemical formula	C2H3Li
Molar mass	33.99 g·mol−1
Appearance	white solid
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	pyrophoric
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation and structure

Solutions of vinyllithium are prepared by lithium-halogen exchange reactions. A halide-free route entails reaction of tetravinyltin with butyllithium:

Sn(CH=CH₂)₄ + 4 BuLi → SnBu₄ + 4 LiCH=CH₂

The reaction of ethylene and lithium affords vinyl lithium and lithium hydride, together with other organolithium compounds,^[1]

Like most organolithium compounds, vinyllithium crystallizes from THF as a cluster compound as a cubane-type cluster.^[2]

Structure of [LiC₂H₃(THF)]₄.

Reactions

Vinyllithium is used to install vinyl groups on metal-based reagents, i.e., vinylations. It is a precursor to vinylsilanes, vinylcuprates, and vinylstannanes.^[3] It adds to ketones compounds to give allylic alcohols. Vinylmagnesium bromide is often used in place of vinyllithium.^[4]

Alternative reagents

Vinyl magnesium bromide, a Grignard reagent, is in many ways easier to generate in the laboratory and behaves similarly to vinyllithium.^[5]