Polyfluorobicyclo[2,2,1]heptanes. Part V. Syntheses using bridgehead carbanions generated by removal of bridgehead hydrogen with aqueous bases

Abstract

Synthetically useful carbanionic intermediates have been generated from 1H-undecafluoro- and from 1H,4H- and 1H,4-trifluoromethyldecafluorobicyclo[2,2,1]heptane with potassium hydroxide in water and an organic co-solvent (methanol, t-butyl alcohol, dimethyl sulphoxide, dimethylformamide, or dioxan). From them were prepared 1-hydroxymethyl-, 1-methyl-, and 1-iodo-undecafluorobicyclo[2,2,1]heptane, undecafluorobicyclo[2,2,1]-heptan-1-ylacetic acid and bis(undecafluorobicyclo[2,2,1]heptan-1-yl)mercury from 1H-undecafluorobicyclo-[2,2,1]heptane: 1,4-bis(hydroxymethyl)-, 1H,4-(hydroxymethyl)-. 1H4-iodo- and 1,4-dimethyl-decafluoro-bicyclo[2,2,1]heptane and bis-(4H-decafluorobicyclo[2,2,1]heptan-1-yl)mercury from 1H,4H-decafluorobicyclo-, [2,2,1]heptane: 4-trifluoromethyldecafluorobicyclo[2,2,1]hept-1-ylmethanol from 1H-4-trifluoromethyldeca-fluorobicyclo[2,2,1]heptane. The intermediate carbanions are stabilised by inductive effects alone since hyper-conjugation would imply unsaturation at the bridgehead.