First Experimental Evidence of an Intramolecular H Bond between Aliphatic Cl and Aromatic C-H

The first example of an intramolecular H bond between aliphatic Cl and aromatic C H was observed in the crystal of C-2-symmetric (4R,5R)-4,5-bis(diphenylchloromethyl)-1,3,2-dioxathiolane 2-oxide. In this case one Cl atom is engaged in H-bonding with two ortho-C H groups in the axial and equatorial phenyl planes, with the recorded distances of 2.562 angstrom and 2.804 angstrom, respectively. The observed angle for Ca-H-Cl is 108.41 degrees and that. for C-q-H-Cl is 96.53 degrees.