Cobalt(III)-catalyzed asymmetric ring-opening of 7-oxabenzonorbornadienes via indole C–H functionalization

Asymmetric ring-opening (ARO) reactions via β-oxygen elimination remained elusive. Here, the authors reported cobalt(III)-catalyzed ARO reaction, offering deep mechanistic insights and the origins of the diastereo- and enantioselectivity.
Published in Chemistry
Cobalt(III)-catalyzed asymmetric ring-opening of 7-oxabenzonorbornadienes via indole C–H functionalization
Like

Share this post

Choose a social network to share with, or copy the shortened URL to share elsewhere

This is a representation of how your post may appear on social media. The actual post will vary between social networks

Asymmetric ring-opening (ARO) of strained bicyclic olefins is an important platform for building-up molecular complexity. Merging ARO reactions with transition-metal-catalyzed C–H activation has become an area of recent interest (Chem. Soc. Rev. 2021, 50, 3013-3093). However, the C–H activation-induced ARO reactions of 7-oxabenzonorbornadienes via β-oxygen elimination remained elusive. Mechanistically, it was regarded that the ARO reactions proceeded via the exo-coordination of a carbon–metal species to the olefin moiety, migratory insertion and cis-β-heteroatom elimination. And the migratory insertion was speculated as the enantioselectivity-determining step in the ARO reactions (Fig. 1).

Fig. 1. Common mechanistic manifold of asymmetric ring-opening of bicyclic alkenes

In this work, high yields and excellent stereoselectivity were obtained for a wide range of cis-ring-opening products under the optimal conditions. More interestingly, the utilization of Cp*Co(CO)I2
as the catalyst led to reversed diastereoselectivities favoring the trans ring-opening products (Fig. 2). 

Fig. 2. Co-cat. asymmetric ring-opening of 7-oxabenzonorbornadienes

Combined experimental and computational studies suggested the mechanistic pictures of the CpCo-catalyzed ARO reactions where cis- and trans-β-oxygen elimination work as the selectivity-determining step for enantioselective and racemic reactions, respectively (Fig. 3). Such results are different from the previous cognition (Angew. Chem. Int. Ed. 2019, 58, 322-326; Angew. Chem., Int. Ed. 2019, 58, 2514-2518).

Fig. 3. Proposed catalytic cycle and mechanism experiment

As an extension, 7-azabenzonorbornadiene could also be applied in the similar ARO reactions in a diastereodivergent manner (Fig. 4).

Fig. 4. ARO reactions of 7-azabenzonorbornadiene

More details of this work could be found here: “Cobalt(III)-catalyzed asymmetric ring-opening of 7-oxabenzonorbornadienes via indole C–H functionalization” in Nature Communications.

Please sign in or register for FREE

If you are a registered user on Research Communities by Springer Nature, please sign in

Subscribe to the Topic

Chemistry
Physical Sciences > Chemistry

Related Collections

With collections, you can get published faster and increase your visibility.

Applied Sciences

This collection highlights research and commentary in applied science. The range of topics is large, spanning all scientific disciplines, with the unifying factor being the goal to turn scientific knowledge into positive benefits for society.

Publishing Model: Open Access

Deadline: Ongoing

Cancer and aging

This cross-journal Collection invites original research that explicitly explores the role of aging in cancer and vice versa, from the bench to the bedside.

Publishing Model: Hybrid

Deadline: Jul 31, 2024