FORMATION OF DELTA-ANIONIC COMPLEXES IN REACTIONS BETWEEN 5-NITROTHIAZOLE, 6-NITROBENZOTHIAZOLE AND TETRABUTYLAMMONIUM BOROHYDRIDE

The title reactions were performed in toluene, tetrahydrofuran (THF) a nd dimethylsulfoxide. H-1 NMR spectral data from the reaction mixtures in Me2SO and in THF indicate that each substrate affords only one res pective sigma-anionic complex. Kinetic data on formation of the comple xes indicate that the attack of the nucleophile and stability of the c omplexes are affected greatly by changing the solvent. In agreement wi th our previous findings, in Me2SO the rate of formation of the comple xes from both substrates considered is lower than that observed in les s polar solvents (toluene and THF). The explanation of this trend incl udes comparison of charge dispersion in the transition state with resp ect to the initial state and the possibility of changes in the hydride ion carrier when the solvent is changed.