Synthetic Studies on Indole Alkaloids by Using Indol-2-yl Carbinol Strategy

Fu-She Han

Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences,

5625 Renmin Street, Changchun, Jilin, 130022, China

       As shown in the Figure, a group of indole alkaloids whose structures feature the presence of fused-ring system and a full carbon quaternary chiral center at C-2 substituents. Except for mersicarpine 1, other products have not yet been synthesized. Their complex structures as well as intriguing biological properties have attracted our great interest toward achieving their total synthesis.

      We have developed a novel and efficient strategy for the construction of quaternary carbon at C-2 substituents by means of acid-catalyzed reaction of indol-2-yl carbinol with appropriate vinyl nucleophiles. This strategy provided a very efficient pathway for the synthesis of mesicarpine 1¹ and construction of the core structure of original assigned tronocarpine 2.² More recently, we also investigated the Brønsted acid-catalyzed asymmetric reaction of indol-yl carbinol derivatives aimed at constructing the chiral quaternary carbon.³ To best use these results, we are now investigating the enantioselective synthesis of more complicated compounds 3–6.

Figure. Some Indole alkaloids containing a full carbon quaternary chiral center at C-2 substituents.

References

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