Chelation- and Non-Chelation-Contrplled Addition of 2-(Trimethylsilyl)thiaszole to alpha-Amino Aldehydes: Stereoselective Synthesis of the beta-Amino-alpha-hydroxy Aldehyde Intermediate for the Preparation of the Human Immunodeficiency Virus Proteina

摘要

The addition of organometallic reagents to chiral N-protected alpha-amino aldehydes to give beta-amino alcohols is receiving considerable attention as a key operation for the synthesis of biologically interesting compounds such as ammo sugars, sphingosinea, and peptidomimetics. Control of the diastereoselectivity has been reported through the change of the metal and/or the presence of an added Lewis acid or chelatihg agent. On the other hand, we have reported some years ago a few yet significant examples of either syn or anti selective addition of 2,(trimethylsilyl)thiazole (2-TST, 1) to some a-amino aldehydes containing a singly (R'＝ H) or doubly (R' ＝/ H) protected nitrogen, respectively (eq 1).