Simple Preparation Process of syn Phenylpropanolamines from Racemic O-TBDPS Cyanohydrins

Abstract

In this article, a practically interesting route for the diastereoselective synthesis of phenylpropanolamines has been demonstrated for the first time. Using racemic O-tert-butyldiphenylsilyl (TBDPS) cyanohydrins as the starting materials, various syn phenylpropanolamines and derivatives (e.g., norpseudophedrine) have been successfully prepared in exellent diastereoselectivity via a practically interesting process.

GRAPHICAL ABSTRACT

Keywords:

• Alkylation
• diastereoselective
• O-TBDPS cyanohydrins
• phenylpropanolamines
• practically interesting

Notes

^a Reaction conditions: O-silyl cyanohydrin 1 (1 mmol), MeMgX (1.5 mmol) in a solvent (3 mL) at 0 °C for 10 h, and then MeOH (3 mL) and NaBH₄ (2 mmol) for more 12 h at rt.

^b Determined by GC using dodecane as internal stardard.

^c Determined by GC or ¹H NMR.

^d nd, not detected.

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