Unformatted text preview: oxonium ion (en route to the enol) is destabilized by the electron withdrawing halide, making subsequent halogenation sluggish. Thus, “over-halogenation” is not a problem. · Halogenation under basic conditions yields products in which ALL alpha-hydrogens have been exchanged for halide. Under basic conditions, the electron withdrawing halide stabilizes the negatively charged enolate. Thus, each bromination accelerates the next under basic conditions. Tri-haloketones can react further to give carboxylates and haloforms. This reaction is known as the haloform reaction. Know the mechanism, · The haloform reaction represents the first example of an “acyl substitution reaction”. This is an important reactions type that we will encounter extensively in forthcoming material. · Midterm Exam I is coming after next weeks two lectures (after lecture 8) – be sure to do homework and attend office hours and review sessions....
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- Spring '08
- Functional group, Carbonyl, THP, electron withdrawing halide