83922-62-7Relevant academic research and scientific papers
Reaction of a Highly Spiro-activated Electrophilic Cyclopropane with Pyridines. The Substituent Effect on the Reaction Rate
Ohkata, Katsuo,Nagai, Takashi,Tamaru, Akira,Nandate, Masa-aki,Hanafusa, Terukiyo
, p. 1255 - 1260 (2007/10/02)
The kinetics of the reactions of 3,3,10,10-tetramethyldispirotrideca-1,5,8,12-tetraone (7) with a series of substituted pyridines were investigated.The compound underwent well behaved second-order reactions with nucleophiles to afford the polar zwitterionic products (9).Values of log k in acetonitrile fall on a straight line when plotted against the pKa values of a series of 3- or 4-substituted pyridines and exhibit a Broensted slope of 0.24.Methyl substitution in the neighbourhood of the reaction centre in the substrate or a nucleophile produced a fall in reactivity to some degree (1/2-1/10).These results together with an unusual solvent effect are interpreted by a preassociative mechanism in which a polar encounter complex is formed prior to the cyclopropane ring opening to give the final product (9).
