I. The Exo-anomeric Effect as a Novel Method for Asymmetric Induction, II. A Fragment Assembly Aldol Approach Toward the Synthesis of the Polypropionate Subunit of Rutamycin B, III. A Sterochemically General Synthesis of 2-deoxyhexoses Via the Asymmetric Allylboration of 2,3-epoxyaldehydes