Diastereoselective radical cyclization of bromoacetals (Ueno-Stork reaction) controlled by the acetal center
作者:Félix Villar、Philippe Renaud
DOI:10.1016/s0040-4039(98)01971-6
日期:1998.11
The stereochemistry of the 5-exo-trig cyclization of bromoacetals (Ueno-Stork cyclization) can be controlled from the stereogenic acetal center. High stereoselectivities have been observed for the formation of 4-substituted tetrahydrofurans. Preparation of an optically pure β-substituted γ-butyrolactone by use of an easily removable chiral auxiliary is reported.
A systematic investigation of radical haloacetal cyclizations (Ueno-Stork reaction) where the acetal center is the unique stereogenic element is reported. This highly diastereoselective reaction can be used for the preparation of polysubstituted tetrahydrofurans and gamma-lactones. We report herein the full experimental details of reactions where up to three new chiral centers are created. To demonstrate