194. Enantioselective preparation and hydroboration of cyclic enamides: Synthesis of (2S)-pseudoconhydrine
     Oppolzer, W.; Bochet, C. G.
     Tetrahedron Lett. 1995, 36, 2959-2962

Successive treatment of 2-alkyl-1-hydroxy-6-carbonylsultampiperidines 1 with NaH and an acylating agent/pyridine in boiling toluene affords optically pure 1-acyl-2-alkyl-1,2,3,4-tetrahydropyridines 2. Hydroboration/oxidation of N-benzoylenamides 2f and 2gfurnishes trans-2-alkyl-1-benzyl-5-hydroxypiperidines5f and 5g, respectively. Hydrogenolysis of 5f provides pure (2S)-pseudoconhydrine (7), in 3 steps from 1, R²=n-C₃H₇ (31 % overall yield).

DOI : 10.1016/0040-4039(95)00439-J 

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