Isopentyl chloride

To determine the structure of a compound from its reactions, the structures of the products are first considered and their formation is then deduced from the reactions. The coupling product must be a symmetrical molecule whose carbon-to-carbon bond was formed between C" and C of 2,7-dimethyloctane. The only RCl which will give this product is isopentyl chloride ... 

The complex nature of alkylation of alkenes is illustrated by the reaction of 1- and 2-chloropropane with ethylene,53 which does not yield the expected isopentyl chloride. Instead, l-chloro-3,3-dimethylpentane is formed by isomerization of the primary product to give fcrf-amyl chloride, which adds to ethylene more readily than do starting propyl halides (Scheme 5.4). The same product is also obtained54 when ethylene reacts with neopentyl chloride in the presence of AICI3. 

Alkyl Chlorides. Hydrochloric acid also promoted the peroxide-induced monoethylation of chloroalkanes. Results with n-butyl chloride, isobutyl chloride and isopentyl chloride are described briefly in this paper. 

The product formed in largest amount by the hydrochloric acid-promoted and peroxide-induced reaction of isopentyl chloride with ethylene was also that formed by alkylation at the tertiary carbon atom, namely 1-chloro-3,3-dimethylpentane (Ig.) (Expt. 25). The remaining constituents of the reaction product were all obtained in very minor amount and were all alkyl chlorides. Among these were 4-chloro-2-methylhexane (y), 1-chlorohexane (formed by telomerization) and some chlorononanes including 5-chloro-3,3-dimethyl-heptane (3 ) formed by ethylation of 12, 4-chloro-2-methyloctane (15) and l-chloro-3-methyloctane (IT). ... 

---