Cyclobutane carboxylic acid chloride

Hydroxydihydronormorphinone Cyclobutane carboxylic acid chloride Lithium aluminum hydride... 

The use of sulfuryl chloride for free radical chlorination of aliphatic carboxylic acids gives mixtures of positional isomers.7 However, with the cyclobutane ring, the attack is much more selective. The present method provides a procedure for free radical halogenation of a cyclobutane ring. 

Tetraethyl butane-1,1,4,4-tetrtacarboxylate added to a soln. of Na in abs. alcohol, to the resulting soln. tetraethyl l,4-dibromobutane-l,l,4,4-tetracarboxy-late added, and heated 4 hrs. in an oil bath at no-IIS -> tetraethyl cyclobutane-1,1,2,2-tetracarboxylate (Y 75.2%) boiled with aq. HGl (1 1) at ISO-HO in an oil bath until the oily layer has dissolved after 35-40 hrs., the HGl removed by distillation, and the residue heated at 180-200° until G0.2-evolution ceases mixture of cis- and frans-cyclobutane-l,2-dicarboxylic acids (Y 97.5%) refluxed 5 hrs. at 70-90° with acetjd chloride on a water bath, excess acetyl chloride and the resulting acetic acid removed by distillation at atmospheric pressure, and the residue heated 6-7 hrs. at 160-175° in an oil bath whereby the mixed anhydride of frans-cyclobutane-l,2-dicarboxylic acid and acetic acid is converted to acetic anhydride and cis-cyclobutane-l,2-dicarboxylic acid anhydride (Y 81.2%) boiled with 2 parts of water cis-cyclobutane-l,2-di-carboxylic acid (Y ca. 100%). V. P. Gol mov and Z. P. Malevannya, 7K. 31, 665 (1961) G. A. 55, 22162b method of ring closure s. J. J. Lennon and W. H. Perkin, Soc. 1928, 1513. 

Addition of methoxycarbonylnitrene generated photochemically from methyl azidoformate to methylenecyclopropane gave methyl l-azaspiro[2.2]pentane-l-carboxylate 1, which cannot be isomerized to the cyclobutane derivative like the isosteric oxaspiropentanes. " Treatment with acids such as hydrogen chloride or methanesulfonic acid cleaved the aziridine ring and gave l-(chloromethyl)-l-(methoxycarbonylamino)cyclopropane and l-(mesyloxymethyl)-l-(methoxycarbonylamino)cyclopropane. ... 

---