Novel methods for making chlorohydrins are provided using a Lewis acid catalyst with an olefin and peroxy compound or where an enantiomer is desired, a Lewis acid catalyst in combination with a chiral alcohol, particularly glycol, and a combination of a peroxy compound and alkenol. In certain situations, an epoxide may be employed.
Herein we report that a single frustratedLewispair (FLP) catalyst can promote the reductive etherification of aldehydes and ketones. The reaction does not require an exogenous acid catalyst, but the combined action of FLP on H2, R‐OH or H2O generates the required Brønsted acid in a reversible, “turn on” manner. The method is not only a complementary metal‐free reductive etherification, but also a niche
TiCl<sub>4</sub>/<i>tert</i>-Butyl Hydroperoxide: Chemioselective Oxidation of Secondary Alcohols and Suppression of Sharpless Epoxidation
作者:Kuangsen Sung、Chun-Tin Shei、Hao-Lun Chien
DOI:10.1055/s-2008-1066997
日期:——
Replacing Ti(Oi-Pr)4 with TiCl4 under the normal Sharpless epoxiation conditions resulted in a shut down of the epoxidation reaction. Instead, a chemioselective oxidation of secondary alcohols in the presence of primary alcohols occurred.