Synthesis of Alkaloid 223A and a Structural Revision
摘要:
[GRAPHICS]Synthesis of alkaloid 223A has been achieved by sequential use of our original conjugate addition reaction to enaminoesters as the key step. The proposed structure for natural 223A (A, absolute configuration unknown) was revised to B, and the relative stereostructure was determined to be 5R*,6R*,8R*,9S* by the present synthesis.
Synthesis of Alkaloid 223A and a Structural Revision
摘要:
[GRAPHICS]Synthesis of alkaloid 223A has been achieved by sequential use of our original conjugate addition reaction to enaminoesters as the key step. The proposed structure for natural 223A (A, absolute configuration unknown) was revised to B, and the relative stereostructure was determined to be 5R*,6R*,8R*,9S* by the present synthesis.
Stereodivergent synthesis of the 2,3,5,6-tetrasubstituted piperidine ringsystem has been achieved by sequential stereocontrolled Michael-type conjugate addition reaction of appropriate enaminoesters. This methodology has been applied to the total syntheses of the poison frog alkaloids 223A and 205B. The relative stereochemistry of natural 223A at the 6-position was revised, and the absolute stereochemistry