Enantioselective iodolactonization to prepare ε-lactone rings using hypervalent iodine
Jenna L Payne1, Zihang Deng1, Andrew L Flach1
1Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University Nashville Tennessee 37235-1822 USA jeffrey.n.johnston@vanderbilt.edu.
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Despite the rapid growth of enantioselective halolactonization reactions in recent years, most are effective only when forming smaller (6,5,4-membered) rings. Seven-membered ε-lactones, are rarely formed with high selectivity, and never without conformational bias. We describe the first highly enantioselective 7-exo-trig iodolactonizations of conformationally unbiased ε-unsaturated carboxylic acids, effected by an unusual combination of a bifunctional BAM catalyst, I2, and I(iii) reagent (PhI(OAc)2:PIDA).
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