Intramolecular Interaction of Adjacent Hydroxymethyl, Formyl, and Carboxyl Groups: Proximity Effect in the Swern Oxidation of cis,cis-1,3,5-Tris(hydroxymethyl)-1,3,5-trimethylcyclohexane.

The proximity effect in the Swern oxidation of cis,cis-1,3,5-tris(hydroxymethyl)-1,3,5-trimethylcyclohexane (4) with TFAA was examined. The oxidation reaction of triol 4 with DMSO, TFAA, and relatively small amounts of triethylamine gave 5-formyl-cis,cis-1,3,5-trimethyl-3-hydroxymethylcyclohexane-1-carboxylic acid hemiacetal (7a) as well as 1,7,9-trimethyl-3,5,12-trioxawurtzitane (6), 5-formyl-cis,cis-1,3,5-trimethyl-3-hydroxymethylcyclohexane-1-carboxylic acid lactone (5), and polymers of cis,cis-1,3,5-triformyl-1,3,5-trimethylcyclohexane (2). Hemiacetal 7a underwent novel solvent-dependent conversions to hemiacetal 7b, lactone 5, or 1,7,9-trimethyl-2-oxo-3,5-dioxatricyclo[5.3.1.04,9]undecane (8) via 5-formyl-cis,cis-1,3,5-trimethyl-3-hydroxymethylcyclohexane-1-carboxylic acid. In the cases of relatively large amounts of triethylamine, trialdehyde 2 was given in moderate yield.