Diastereoselective Synthesis of Nonracemic 2-Alkyl-5-Hydroxypiperidines with (2R,5S)-Configuration via a Tandem Wittig [2+3] Cycloaddition Reaction. Synthesis of epi-Pseudoconhydrine and Its Homologs - Herdeis, Claus; Schiffer, Thomas (Synthesis, 1997)