Pd(II)/(t)Bu-quinolineoxazoline: an air-stable and modular chiral catalyst system for enantioselective oxidative cascade cyclization.

An air-stable and structurally tunable chiral (t)Bu-quinolineoxazoline/Pd(II) catalyst system has been developed for the enantioselective oxidative cascade cyclization of a variety of disubstituted olefinic substrates, with the apparent advantages of good yields and excellent enantioselectivities (up to 98% ee) and diastereoselectivities (dr >24:1). A transition-state model has also been proposed to account for the excellent stereocontrol.