1-bromo-1-lithioethene: a practical reagent for the efficient preparation of 2-bromo-1-alken-3-ols.
A reliable preparative-scale synthesis of 1-bromo-1-lithioethene is reported. This reagent undergoes clean 1,2-addition with a range of aldehydes and ketones at -105 degrees C to afford the corresponding 2-bromo-1-alken-3-ols in moderate to excellent yield. Efficient diastereoselective addition to alpha-siloxy and alpha-methylcyclohexanones, as well as protected 3-keto furanose sugars, is achieved in the presence of 10 mol % CeBr(3). The resulting bromoallylic alcohol adducts have considerable potential as synthetic building blocks. [reaction: see text]
Novikov
Yehor Y
YY
Department of Chemistry, Kent State University, Kent, Ohio 44242, USA. ynoviko1@kent.edu
Sampson
Paul
P