Identification of molecular crystals capable of undergoing an acyl-transfer reaction based on intermolecular interactions in the crystal lattice.
Investigation of the intermolecular acyl-transfer reactivity in molecular crystals of myo-inositol orthoester derivatives and its correlation with crystal structures enabled us to identify the essential parameters to support efficient acyl-transfer reactions in crystals: 1) the favorable geometry of the nucleophile (-OH) and the electrophile (C-O) and 2) the molecular assembly, reinforced by C-H⋅⋅⋅π interactions, which supports a domino-type reaction in crystals. These parameters were used to identify another reactive crystal through a data-mining study of the Cambridge Structural Database. A 2:1 co-crystal of 2,3-naphthalene diol and its di-p-methylbenzoate was selected as a potentially reactive crystal and its reactivity was tested by heating the co-crystals in the presence of solid sodium carbonate. A facile intermolecular p-toluoyl group transfer was observed as predicted. The successful identification of reactive crystals opens up a new method for the detection of molecular crystals capable of exhibiting acyl-transfer reactivity.
Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune-411008 (India), Fax: (+91) 20-25902629.
Majid I
MI
Tamboli
Shobhana
S
Krishnaswamy
Rajesh G
RG
Gonnade
Mysore S
MS
Shashidhar
X-ray diffraction; acylation; domino reactions; intermolecular interactions; solid-state reactions