MgI2-catalyzed halo aldol reaction: a practical approach to (E)-?-iodovinyl-??-hydroxyketones (original) (raw)

T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 4 2 8 9 3 O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 2 8 9 3 -2 8 9 6 OBC www.rsc.org/obc A novel generation of 1-iodo-3-siloxy-1,3-butadienes has been developed by reacting trimethylsilyl iodide (TMS-I) with a,b-unsaturated ketones in dichloromethane at 0 °C without the use of any catalyst. The halo aldol reaction of these butadiene intermediates with aldehydes was efficiently carried out by using magnesium iodide as the catalyst. Twelve b-iodo-a,b-unsaturated-b-hydroxyketones (halo aldols) have been synthesized under the new condition with excellent geometric selectivity and good chemical yields (>80% chemical yields for 11 examples).