Improved Stereoselective Syntheses of (+)‐Valiolamine and (+)‐Valienamine Starting from (–)‐Shikimic Acid

Improved stereoselective syntheses of the target compounds (+)‐valiolamine 1 and (+)‐valienamine 2 starting from naturally abundant (–)‐shikimic acid are described. A common key intermediate compound 7 was first synthesized from (–)‐shikimic acid in 9 steps. The compound 7 was then converted to (+)‐valiolamine 1 in 3 steps, and was also converted to (+)‐valienamine 2 in 4 steps. In summary, (+)‐valiolamine 1 and (+)‐valienamine 2 were synthesized from (–)‐shikimic acid in 12 (or 13) steps in 40% and 39% overall yields, respectively. The present syntheses are more practical and might be important for the potential industrial preparations of pharmaceutically valuable (+)‐valiolamine 1 and (+)‐valienamine 2 .