L-Bromo-3-chlorocyclobutane, with

Wurtz reaction The coupling of two alkyl halides, RX, with sodium metal to give the R-R compound. Usually of almost no synthetic value as there are many side reactions. However, the intramolecular reaction of l-bromo-3-chlorocyclobutane with sodium gives bicyclobutane in about 95% yield. 

Deoxyiodination has been used for the synthesis of 17 (n = 4). ° For the preparation of bi-cyclo[1.1.0]butane 17 (n = 1) and congeners thereof, special conditions are required. Reaction of l-bromo-3-chlorocyclobutane with sodium in refluxing dioxane gave bicyclo[l. 1. OJbutane in 90% yield a detailed experimental procedure is given.Hexamethylbicyclo[l, 1.0]butane was similarly obtained in 75% yield using sodium-potassium alloy in 1,2-dimethoxyethane. ... 

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