Enantiopure 2,9‐Dideuterodecane – Preparation and Proof of Enantiopurity

Abstract

(R,R)‐ and (S,S)‐(2,9‐2H2)‐n‐Decane were prepared regio‐ and stereospecifically in 25–26 % yield over five steps from commercially available enantiopure (R)‐ and (S)‐propylene oxide, respectively. The synthetic procedure involved nucleophilic displacement of (R)‐ and (S)‐4‐toluenesulfonic acid 1‐methyl‐4‐pentenyl ester with LiAlD4 to furnish the respective (5‐2H)‐1‐hexenes. Subsequent olefin metathesis and reduction of the double bond furnished the title compounds. The optical purity of (R,R)‐ and (S,S)‐(2,9‐2H2)‐n‐decane could not be determined by chromatography or polarimetry. Therefore, (R,R)‐ and (R,S)‐(5‐2H)‐3‐hydroxy‐2‐hexanone were prepared from their respective hexenes by Wacker oxidation, followed by enantioselective α‐hydroxylation. The enantiopurity could then be determined by NMR spectroscopy because the stereospecifically deuterated hydroxyketones showed separated signals for the subterminal carbon atom (C‐5) in the 13C NMR spectrum.