Highly Stereoselective and Flexible Synthesis of 6-Alkoxy-5,6-dihydro-4H-1,2-oxazines by Conjugate Addition of Organolithium Compounds to 6H-1,2-Oxazines Followed by Trapping with Electrophiles - Buchholz, Monika; Reissig, Hans-Ulrich (Synthesis, 2002)