Total Synthesis of Himalensine A (J. Xu, 2019)

draft 17-June-2020

Himalensine A (1) is a member of the daphniphyllum alkaloids isolated in 2016 from Daphniphyllum himalense, a plant which is originated from the southern Himalaya region, and published in Organic Letters. In 2019 the research group of Jing Xu (徐晶) from SUSTech Shenzhen (China) published the second total synthesis of this complex alkaloide in the journal Angewandte Chemie. From a retrosynthetic point of view, they decided to introduce the cyclopentenone moiety in a late stage transformation as shown in Figure 1. Precursor 2 should be synthesized by a challenging Heck coupling. Finally tricyclus 3 should be available by nitrile hydration from unsaturated ketone 4.

Figure 1: Retrosynthetic analysis for the total synthesis of himalensine A (1) by the Xu group.