Oxalyl Chloride as a One and Two Carbon Synthon. A Cyclic Carbonate with a Tetraoxa(3.3.3)propellane Skeleton.-The chelation-directed reaction of bromomagnesium-2-tert-butylphenolate with oxalyl chloride (II) leads to formation of a cyclic carbonate (III) with a hitherto unknown tetraoxa (3.3.3) propellane skeleton along with minor amounts of the expected glyoxalyl chloride (IV). -(GRIENEISEN, J.-L.; BIRBAUM, J.-L.; Tetrahedron Lett. 35 (1994) 40, 7359-7360; Ciba-Geigy AG, CH-1723 Marly, Switz.; EN)