L-Bromo-3-chlorocyclobutane

In the case of an intramolecular Wurtz reaction less side-reactions are observed this variant is especially useful for the construction of strained carbon skeletons. For example bicyclobutane 5 has been prepared from l-bromo-3-chlorocyclobutane 4 in a yield of > 90% ... 

The conversion of l-bromo-3-chlorocyclobutane to bicyclo-[l.l.OJbutane is described in Organic Syntheses.n... 

The conversion of 3-chlorocyclobutanecarboxylic acid to l-bromo-3-chlorocyclobutane is described in Organic Syntheses.8... 

In l-bromo-3-chlorocyclobutane there are cis and trans isomers, but no enantiomers C and C are not chiral, because a plane perpendicular to the ring bisects them and their four substituents. The sequence of atoms is identical going around the ring clockwise or counterclockwise from C to C. ... 

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. 

HunsdieckerCristol reaction. (1, 657). A detailed procedure for the preparation of l-bromo-3-chlorocyclobutane by the modified Hunsdiecker reaction has been published.1 A 1-1. three-necked, round-bottomed flask wrapped with aluminum foil to exclude light and equipped with a mechanical stirrer, a reflux condenser, and an addition funnel, is charged with 37 g. (0.17 mole) of red mercuric oxide and 330 ml. 

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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