cg6b01322_si_001.pdf (3.7 MB)
Helical Preorganization of Molecules Drives Solid-State Intermolecular Acyl-Transfer Reactivity in Crystals: Structures and Reactivity Studies of Solvates of Racemic 2,6-Di‑O‑(4-fluorobenzoyl)-myo-inositol 1,3,5-Orthoformate
journal contribution
posted on 2016-12-07, 00:00 authored by Shobhana Krishnaswamy, Mysore S. Shashidhar, Mohan M. BhadbhadeRacemic
2,6-di-O-(4-fluorobenzoyl)-myo-inositol
1,3,5-orthoformate yielded structurally dissimilar solvent-free
and solvated crystals depending upon the solvent of crystallization.
The solvated crystals exhibited helical assembly of host molecules,
due to the interaction of the guest molecules with the orthoformate
moiety of the host. Some of the solvates showed specific but incomplete
benzoyl group transfer reactivity below the phase transition temperature,
whereas the reaction in solvent-free crystals led to a mixture of
several products. These results reveal the necessity of helical molecular
packing of the reacting molecules in their crystals to facilitate
specific intermolecular acyl transfer reactivity. The crystal structures
of the fluorobenzoate solvates were similar to those of the solvates
of the analogous chloro and bromobenzoates. The latter could be thermally
transformed into their solvent-free form via melt crystallization,
resulting in the conversion of a helical molecular packing into a
nonhelical molecular packing.