title: Suppressed beta-effect of silicon in 3-silylated monocyclic beta-lactams: the role of antiaromaticity.
abstract: The beta-stabilizing effect of silicon substituent at C-3 on a C-4 cation and a radical in the 2-azetidinone systems is studied using NMR kinetics. While the beta-effect is virtually nonexistent in the case of a cation, a foiled beta-effect (only a 3-fold rate enhancement) is observed for a radical intermediate. From both the experimental and theoretical studies, it is demonstrated that antiaromaticity is playing the prime role in suppressing the beta-stabilizing effect of silicon.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Guwahati-781039, India. ssbag75@iitg.ernet.in
authors.forename: Subhendu Sekhar
authors.initials: SS
authors.lastname: Bag
authors.forename: Rajen
authors.initials: R
authors.lastname: Kundu
authors.forename: Amit
authors.initials: A
authors.lastname: Basak
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Slanina
mesh_terms: D001384:Azetidines / Q000737:chemistry; D015394:Molecular Structure; D008997:Monobactams / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: C116379:2-azetidinone; D001384:Azetidines; D008997:Monobactams; D012825:Silicon