Transition metal catalyzed valence isomerizations of tricyclo[4.1.0.02,7]heptane. Evidence for an organometallic intermediate

Synthesis of 1,3-disubstituted bicyclo[1.1.0]butanes via directed bridgehead functionalization

“…With sulfone and amide directing groups successfully identified, cross-coupling of the resultant carbanions was addressed. The use of palladium catalysis for the synthesis of functionalized BCBs could potentially be problematic due to competing rearrangements in which Pd( ii ) species promote electrophilic cleavage of the C1–C3 bond to give ring-opened diene products, 41–43 a process that is of value in the synthesis of functionalized cyclobutanes. 17 We anticipated that the pi-acidity of palladium complexes could be lowered by the use of electron-rich ligands, enabling the selective cross-coupling of metalated BCBs while avoiding rearrangement.…”

Hydronium ion activity in strongly acidic media. Remarkable agreement between independent estimates

“…It can be seen that this quantity ( ), although nonzero, does not differ vary significantly from zero, varying from -0.2 to +0.4 with a standard deviation of +0.3.7 The agreement between the two approaches must be considered highly satisfactory, especially in view of the fact that both (6) Relative to TEA+ at least, since single ion activities and hence ratios such as /recZ/Fec+ can never be measured absolutely. (7) These differences (from zero), which remain after correcting both scales to the same reference (TEA+), are almost certainly attributable to the method of estimating log a* + and not to the method of measuring Hgf•8 However, although the latter method is more direct, and presumably less subject to error, the Hgf function, and hence the an* values based on it, are referred to a less suitable standard ion, Fec+. It appears the best approach would be to measure an + directly using the polarographic-glass electrode technique, and then try to correct these values to a more suitable standard reference ion, such as TEA+.…”

“…500 cal/mol. Hydrogen abstraction from toluene by f-BuOO will (7) As quoted in H. C. Brown and Y. Okamoto, J. Amer. Chem.…”