Organic reactions in water: an efficient zinc-mediated stereoselective synthesis of (E)- and (Z)-trisubstituted alkenes using unactivated alkyl halides.

[reaction: see text] Treatment of the acetyl derivatives of the Baylis-Hillman adducts 3-hydroxy-2-methylene-alkanoates and 3-hydroxy-2-methylene-alkanenitriles with unactivated alkyl halides in the presence of Zn in saturated aqueous NH(4)Cl solution at room temperature afforded (2E)-2-substituted-alk-2-enoates in the first case and (2Z)-2-substituted-alk-2-enenitriles with high (Z)-selectivity in the second case.