Experimental tests for special stabilization (spiroaromaticity) in a spiro[2.3]hexadienyl anion compared with a series of spiro[2.3]hex-4-en-6-yl anions using polarography and kinetic acidity measurements reveal no significant stabilization. The kinetic acidity data were obtained by hydroxide ion catalyzed tritium exchange in dimethyl sulfoxide-water mixtures. The second-order rate constants were determined to be as follows: for 12,4.6 10-5; for 13, 24.14 × 10-5; for 14, 2.03 × 10-5; for 15 (mixture of isomers), 5.70 × 10-5. Brpnsted coefficients (3) of ca. 0.80 for proton abstraction from the spiro[2.3]hexadiene 12 and spiro[2.3]hex-4-ene 13 suggest that the transition states from both compounds resemble the carbanionic products.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry