Butane 2,3-dibromo-2,3-dimethyl

C6H12Br2 1,2-dibromo-3,3-dimethyl butane 640-21-1 301.65 21.161 2 8654 C6H13Br 2-bromo-3-methyl pentane 62168-41-6 186.68 9.535 2... 

C6H10O2 2-methyl-2-pentenoic acid 3142-72-1 20.299 119.873 2 8247 C6H12Br2 1,4-dibromo-2,3-dimethyl butane 54462-70-3 18.534 151.713 1,2... 

The most convenient synthesis of 1,3-dimethylbicyclo[1.1.0]butane (4) employs the following two-step process.2 Hydrogen bromide is added to allene and/or methylacetylene to give a mixture of cis- and /rans-l,3-dibromo-l,3-dimethyl-cyclobutanes (3). This mixture is stirred with a suspension of 2% lithium amalgam in dioxane for 48 hours at room temperature (4) is obtained in 85% yield. 

A soln. of the startg. azine in anhydrous ether added to a stirred soln. of 1.6 M n-butyllithium in ether-hexane followed after 1 hr. by 2,3-dibromo-2,3-dimethyl-butane, and the crude intermediate heated 1 hr. on a steam bath with 30%-H2O2, NaOH, and ethanol 3,4,6-triphenylpyridazine. Overall Y 78%. F. e., also C-alkylation and coupling of phenylhydrazones and oximes, s. F. E. Henoch, K. G. Hampton, and C. R. Hauser, Am. Soc. 91, 676 (1969). 

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