Regioselective Opening of Epoxy Alcohols: Mild Chemo- and Stereoselective Preparation of Iodohydrins and 1,2-Diols

Article abstract of DOI:10.1021/jo00021a045

Several 2,3-epoxy alcohols have been opened, at -60 deg C, with MgI2, leading to the corresponding 3-iodo 1,2-diols with a high level of regio- and chemoselectivity.The iodohydrins can be reduced "in situ", by means of nBu3SnH, to the corresponding 1,2-diols.The chemo-, regio-, and stereocontrol of the reaction makes the method of wide use.Furthermore, epoxy alcohol derivatives (acetyl, benzyl, or TBMS) still maintain a strong preference for C-3 attack of the nucleophile.The experimental data strongly suggest that a metal (Mg) centered chelate is formed throughout the reaction, which gives rise to the regioselective delivery of the iodiode ion.