Chlorine, reaction with 2-butyne

Chlorination of cyclohexylamine with i-butyl hypochlorite, 45,16 Chlorine, reaction with 2-butyne, 46, 34... 

Related to ketene cycloadditions are the group of cycloadditions with vinyl cation intermediates. The reaction between 2-butyne 6.120 and chlorine giving the dichlorocyclobutene 6.122 is the Smirnov-Zamkow reaction, and there is a similar reaction between allene 6.123 and hydrogen chloride giving the... 

Perfluorocyclopentene is exceptional in being obtained from non-fluorinated materials by a simple one-step procedure, i.e. displacement of chlorine in perchlorocyclopentene by fluoride ion [51], although some polyfluorochloro- and polyfluorohydro-alkenes can be made by analogous processes [51, 52]. If a perfluorocarbon is used as the reaction medium with potassium fluoride/18-crown-6 complex, then a variety of products may be obtained, including hexafluoro-2-butyne [53]. 

Preceding sections focused on acid-base reactions of the C=C rmit of alkenes with various acids. Because the 7t-bond of the alkene reacts, it is reasonable to assume that the 7t-bond of an alkyne may also react with these reagents, and there should be great similarities in the chemical reactivity. Indeed, this is the case. In the experiment where 3,3-dimethyl-l-butyne is treated with HCl in acetic acid, the major product is 2-chloro-3,3-dimethyl-l-butene (92), in up to 75% yield, although the acetic acid reacted with the product to give other products (ketones). This secondary reaction will not be discussed so that the focus will be on the C=C unit in the product (92) and the position of the chlorine in that alkene. 

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