Tetrahedron letters

Thio-claisen rearrangement approach to the synthesis of 2, 3-disubstituted 4-piperidones

F Tubéry, DS Grierson, HP Husson

Index: Tubery, Francoise; Grierson, David S.; Husson, Henri-Philippe Tetrahedron Letters, 1987 , vol. 28, # 51 p. 6461 - 6464

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Citation Number: 8

Abstract

The thiopiperidone , prepared from (Lawesson's reagent, 85 %), underwent rapid reaction with allyl bromide to give the 5,6-dihydropyridinium salt . By reaction of with the appropriate Grignard reagents the C-2 functionalized intermediates were obtained. Heating (R = Pr) at 120°C in DME resulted in formation of the cyclized compounds whereas in the presence of added propionic anhydride the thio-ester was obtained. Under these latter conditions (R = C 5 H 11 ...