Neophyl chloride

Neophyl chloride

Names
IUPAC name (2-chloro-1,1-dimethylethyl)benzene
Other names (Chloro-tert-butyl)benzene
Identifiers
CAS Number	515-40-2
ChemSpider	61498
Jmol interactive 3D	Image
PubChem	68191
InChI InChI=1S/C10H13Cl/c1-10(2,8-11)9-6-4-3-5-7-9/h3-7H,8H2,1-2H3 Key: DNXXUUPUQXSUFH-UHFFFAOYSA-N InChI=1/C10H13Cl/c1-10(2,8-11)9-6-4-3-5-7-9/h3-7H,8H2,1-2H3 Key: DNXXUUPUQXSUFH-UHFFFAOYAJ
SMILES ClCC(c1ccccc1)(C)C
Properties
Chemical formula	C10H13Cl
Molar mass	168.663 g/mol
Appearance	colorless liquid
Density	1.047 g/cm^3
Boiling point	223 °C (433 °F; 496 K)
Solubility in water	organic solvents
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Neophyl chloride, C₆H₅C(CH₃)₂CH₂Cl, is a halogenated organic compound with unusual nucleophilic substitution properties. Neophyl chloride is used to form a versatile organolithium reagent, neophyl lithium, by reaction with lithium.^[1][2]

Preparation

Neophyl chloride was first synthesized by Haller and Ramart by reacting the chlorinating reagent thionyl chloride with neophyl alcohol:

C₆H₅C(CH₃)₂CH₂OH + SOCl₂ → C₆H₅C(CH₃)₂CH₂Cl + HCl + SO₂

It is easily prepared on a large scale by combining benzene and methallyl chloride in the presence of a catalytic quantity of sulfuric acid.^[3] The reaction is an example of an electrophilic aromatic substitution.

H₂C=C(CH₃)CH₂Cl + C₆H₆ → C₆H₅C(CH₃)₂CH₂Cl

Alternatively tert-butylbenzene can be chlorinated with sulfuryl chloride.

Reactions and applications

Neophyl chloride can be used to form an organolithium reagent, neophyl lithium, by reaction with lithium. Organolithium reagents are useful due to their nucleophilic properties and their ability to form carbon to carbon bonds, like in reactions with carbonyls.

C₆H₅C(CH₃)₂CH₂Cl + Li → C₆H₅C(CH₃)₂CH₂Li

Neophyl chloride is of interest to organic chemists due to its substitution properties. Neophyl chloride is a neopentyl halide which means it is subject to the neopentyl effect. This effect makes SN₂ nucleophilic substitution highly unlikely because of steric interactions due to the branching of the β-carbon. No rotamer of the molecule would allow a backside attack of the α carbon.

β-Hydride elimination also does not occur with neophyl derivatives as this group lacks hydrogens at the β positions. These factors make neophyl chloride a precursor to intermediates that resist common substitution and elimination reactions.

References

1. Lide, R. D.; CRC Handbook of Chemistry and Physics. 2003, 590. ISBN 0-8493-0595-0
2. Andrew Streitwieser and Clayton H. Heathcock. Introduction to Organic Chemistry. 3rd ed. New York: Macmillan Co., 1985. ISBN 0-02-946720-9
3. W. T. Smith, Jr. and J. T. Sellas (1963). "Neophyl chloride". Org. Synth.