Jia Zheng
My research is focused on sequential constructions of several chiral centers via Ir-catalyzed asymmetric hydrogenation (Scheme 1). We first attempted the asymmetric hydrogenation of aromatic olefins with our chiral catalyst, affording high enantioselectivity. Subsequently, these products were employed in the Birch reduction, which broke the aromaticity and generated 1,4 dienes/trienes. By the hydrogenations of these 1,4 dienes/trienes, we can create additional chiral centers inside the ring.
The most recent project concerned the preparation of the natural sesquiterpene Juvabione via sequential asymmetric and regioselective hydrogenations. Two adjacent stereogenic centers were constructed, the first generated by hydrogenation of a styrene-type double bond (99% ee). Successively, the mono-hydrogenation of a diene intermediate was employed as key step, granting high levels of regio- and stereocontrol (94:6 dr). This strategy allowed to obtain (−)-juvabione from simple starting materials in 9 steps and 17% total yield.[1]
References:
[1]. Zheng, J.; Margarita, C.; Krajangsri, S.; Andersson, P. G. Org. Lett. 2018, 20, 5676-5679.