title: Stereoselective cyclotetramerization of a 3-(Hydroxymethyl)salicylaldehyde
abstract: Both 3-(hydroxymethyl)-5-methylsalicylaldehyde and its acetonide condense in the presence of hydrogen chloride in ether to form macrocyclic S(4)-symmetric tetraacetal 2. The reaction is completely oligo- and stereoselective, forming only the tetramer and only the achiral (R,S,R,S)-stereoisomer. Acid-catalyzed equilibration studies and molecular mechanics calculations indicate that the stereoselectivity is thermodynamic in origin. In the crystal the saddle-shaped molecules of 2 form coaxial stacks reminiscent of the packing of Pringles potato chips.
authors.affiliation: Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA.
authors.initials: GM
authors.lastname: Butler
authors.initials: SN
authors.lastname: Brown
authors.initials: RM
authors.lastname: Boger
authors.initials: MT
authors.lastname: Ferfolia
authors.initials: AC
authors.lastname: Fitzgibbons
authors.initials: AC
authors.lastname: Jongeling
authors.initials: SJ
authors.lastname: Kelleher
authors.initials: AD
authors.lastname: Malec
authors.initials: J
authors.lastname: Malerich
authors.initials: AN
authors.lastname: Weltner