Trevor G. Bonner

Electrophilic substitution of methoxybenzenes by pentadienyltricarbonyliron cations

Abstract The kinetics of reactions of some open-chain pentadienyltricarbonyliron cations with 1,3-dimethoxy- and 1,3,5-trimethoxybenzene, for which observable equilibria are found, are discussed. These reactions contrast with those previously reported, which go essentially to completion.

A detailed investigation of the acid-catalysed formation of acetals from acetone and D-glucitol

Abstract The acid-catalysed acetonation of D -glucitol has been studied in detail. The true complexity of the reaction, giving the 1,2- and 3,4-monoacetals, the 1,2:3,4-, 3,4:5,6-, and 1,2:5,6-diacetals, and the 1,2:3,4:5,6-triacetal, has been shown. These studies have been carried out mainly by gas-liquid chromatographic techniques, and have shown that, with acetone, the primary hydroxyl group at C-1 is more reactive than that at C-6. The structures of the various acetals have been verified by p.m.r. spectroscopy.

Butylidene acetals of galactitol

Abstract The acid-catalysed reaction of galactitol with butyraldehyde yields the 1,3- and 2,3-mono- and 1,3:4,6-di-acetals, the structures of which were proved by chemical methods. The separation of acetals on an anion-exchange resin is described. Mass spectrometry and n.m.r. spectroscopy were used for characterisation of the methylated acetals and certain partially methylated derivatives of galactitol derived therefrom.

2,4:3,5-di-O-benzylidene-D-glucitol

Abstract Chemical proof is given that the acetal groups in the known 2,3,4,5-di- O -benzylidene- D -glucitol span the 2,4- and 3,5-positions.

Electrophilic Substitution of 1,3-Dimethoxybenzene By Pentadienyltricarbonyliron Cations

Abstract Kinetics of reactions of several open-chain pentadienyltricarbonyliron cations with 1,3-dimethoxybenzene have been studied; the reactions are faster than those of the cyclohexadienyltricarbonyliron cation and a mechanism is proposed.

Butylidene acetals of d-mannitol and their n.m.r. spectra

Abstract The condensation of butyraldehyde and d -mannitol has been studied, and the 1,3:2,5:4,6-tri-, 1,3:4,6- and 1,3:5,6-di, and 1,3- and 3,4-monoacetals have been characterised. Their n.m.r. spectra have been determined, and assignments made that confirm the ring sizes.

Acid-catalysed monoacetalation of two 3-deoxyhexitols

Abstract Acid-catalysed monobutylidenation of 3- deoxy - d -ribo- hexitol yields the 2,4-acetal as the sole, detected product. 3- Deoxy - l -xylo- hexitol yields the 4,5-acetals as kinetic products, and the 4,6-acetal as the thermodynamic product.

Opening of cyclic acetals by trichloro-, dichloro-, and tribromo-borane

The rate-determining step in the ring opening of cyclic acetals by trichloroborane to yield α-chloro-ethers is shown to be consistent with the formation of an oxocarbenium ion. Subsequent reduction provides a general route for the conversion of a diol into a hydroxy-ether. Tribromoborane is a more powerful and dichloroborane a less powerful reagent than trichloroborane.

Acid-catalysed monoacetalation of some 2-deoxyalditols

Abstract Acid-catalysed monobutylidenation of 2-deoxy- D - arabino -hexitol, 2-deoxy- D - lyxo -hexitol, and 2-deoxy- D - erythro -pentitol yielded a 1,3-monoacetal as a kinetic product in each reaction. The thermodynamic products were 4,6-monoacetals from 2-deoxy- D - arabino -hexitol and 2-deoxy- D - lyxo -hexitol, and a 3,5-monoacetal from 2-deoxy- D - erythro-pentitol 2-Deoxy- D -lyxo-hexitol also yielded diastereoisomeric 4,5-monoacetals.

Acid-catalysed formation of diacetals from butyraldehyde and certain D-glucitol derivatives

Abstract Acid-catalysed dibutyiidenation of 1-deoxy- D -glucitol and 3- O -methyl- D -glucitol yields the 2,4:5,6-diacetals as the main, thermodynamically controlled products, and 2-deoxy- D - arabino -hexitol ( i.e. , 2-deoxy- D -glucitol) yields the 1,3:4,6-diacetal as the main, thermodynamically controlled product.