Short I⋯O Interactions in the Crystal Structures of Two 2-Iodo-Phenyl Methyl-Amides as Substrates for Radical Translocation Reactions

Radical translocation reactions are finding various uses in organic synthesis, in particular the stereospecific formation of complex natural products. In this work, the syntheses and single-crystal structures of two substituted 2-iodo-phenyl methyl-amides are reported, namely cyclo-propane carboxylic acid (2-iodo-phenyl)-methyl-amide, C11H12INO (1), and cyclo-heptane carboxylic acid (2-iodo-phenyl)-methyl-amide, C15H20INO (2). In each case, the methyl-amide group has a syn conformation, and this grouping is perpendicular to the plane of the benzene ring: these solid-state conformations appear to be well setup to allow an intramolecular hydrogen atom transfer to take place as part of a radical translocation reaction. Short intermolecular I⋯O halogen bonds occur in each crystal structure, leading to [010] chains in 1 [I⋯O = 3.012 (2) Å] and isolated dimers in 2 [I⋯O = 3.024 (4) and 3.057 (4) Å]. The intermolecular interactions are further quantified by Hirshfeld surface analyses.

[1]  P. Hobza,et al.  Real-space imaging of anisotropic charge of σ-hole by means of Kelvin probe force microscopy , 2021, Science.

[2]  E. Tiekink,et al.  Utilizing Hirshfeld surface calculations, non-covalent interaction (NCI) plots and the calculation of interaction energies in the analysis of molecular packing , 2019, Acta crystallographica. Section E, Crystallographic communications.

[3]  Pierangelo Metrangolo,et al.  Definition of the halogen bond (IUPAC Recommendations 2013) , 2013 .

[4]  A. Chattopadhyay,et al.  Total synthesis of (+)-blastmycinone and formal synthesis of (+)-antimycin A3b☆ , 2007 .

[5]  Pierangelo Metrangolo,et al.  Halogen bonding based recognition processes: a world parallel to hydrogen bonding. , 2005, Accounts of chemical research.

[6]  Atsushi Shirai,et al.  A formal synthesis of martinelline via a combination of two types of radical reactions , 2004 .

[7]  M. Spackman,et al.  Fingerprinting intermolecular interactions in molecular crystals , 2002 .

[8]  Frank H Allen,et al.  Applications of the Cambridge Structural Database in organic chemistry and crystal chemistry. , 2002, Acta crystallographica. Section B, Structural science.

[9]  P. Renaud,et al.  Radicals in Organic Synthesis , 2001 .

[10]  P. Fuchs,et al.  Synthesis via Vinyl Sulfones. Part 73. Free Radical Self-Immolative 1,2-Elimination and Reductive Desulfonylation of Aryl Sulfones Promoted by Intramolecular Reactions with ortho-Attached Carbon-Centered Radicals. , 1998 .

[11]  P. Fuchs,et al.  Free Radical Self-Immolative 1,2-Elimination and Reductive Desulfonylation of Aryl Sulfones Promoted by Intramolecular Reactions with Ortho-Attached Carbon-Centered Radicals(1). , 1997, The Journal of organic chemistry.

[12]  M. L. Navacchia,et al.  Rearrangements and cyclizations in vinyl radicals. Unusual example of 1,4-radical translocation , 1996 .

[13]  D. Curran,et al.  Radical translocation reactions of vinyl radicals : substituent effects on 1,5-hydrogen-transfer reactions , 1993 .

[14]  J. Storey,et al.  Aryl Radical Cyclizations Involving an Amide Group in the Linking Chain. , 1993 .

[15]  M. C. Etter.  Encoding and decoding hydrogen-bond patterns of organic compounds , 1990 .

[16]  K. Houk,et al.  Transition structures for intramolecular hydrogen-atom transfers: the energetic advantage of seven-membered over six-membered transition structures , 1987 .

[17]  A. Bondi.  van der Waals Volumes and Radii , 1964 .

[18]  J. Storey,et al.  Aryl radical cyclisations involving an amide group in the linking chain , 1992 .

[19]  J. E. Boggs,et al.  Substituent-induced asymmetry of the cyclopropane ring , 1972 .