Neophyl chloride

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. 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.