The Vespiary
The Hive => Chemistry Discourse => Topic started by: xxxxx on May 25, 2004, 06:54:00 PM
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i recall reading somewhere that when hcl is added to a double bond in ethyl ether the addition is 88% "syn" and in nitromethane the addition is 100% "anti". dichloromethane is somewhere intermediate between these two. what do these terms "syn" and "anti" mean? does it mean the sterochemistry of the product can be controlled by the solvent choice?
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The stereochemistry will not be affected, but the regioselectivity will. Depending on the mechanism you may end up with different diastereomers but not different enantiomers.
Addition of a halogen (X2) to an alkene to give a di-haloalkane can be either syn- (yielding the cis-dihaloalkane) or anti- (giving the trans-dihaloalkane).