A rhodium catalyzed cycloisomerization and tandem Diels–Alder reaction for facile access to diverse bicyclic and tricyclic heterocycles. Issue 18 (12th April 2019)

• Record Type: Journal Article
• Authors: Zhou, Yirong; Nikbakht, Ali; Bauer, Felix; Breit, Bernhard
• Is Part Of: Chemical science. Volume 10:Issue 18(2019)
• Page Start: 4805
• Page End: 4810
• Publication Date: 2019-04-12
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9sc00980a
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : A rhodium catalyzed cycloisomerization of 1, 6-allenenes successfully prepared six-membered ring exocyclic 1, 3-dienes. Further tandem Diels–Alder reaction with various dienophiles provided diverse bicyclic and tricyclic heterocycles. This methodology is characterised by complete atom and step economy, low catalyst loading, and excellent chemo-, regio-, and diastereoselectivity. Abstract : A regioselective distal cycloisomerization of 1, 6-allenenes was successfully developed to afford six-membered ring exocyclic 1, 3-dienes employing a rhodium/diphosphine catalyst system. Deuterium labelling experiments and DFT calculations were performed to provide insights into the reaction mechanism of this unprecedented transformation. In addition, one-pot tandem Diels–Alder reactions with various dienophiles could readily construct diverse bicyclic and tricyclic nitrogen heterocycles, which are ubiquitous core scaffolds for a variety of natural products and bioactives. High efficiency and exclusive chemo and regioselectivities for a broad substrate scope were achieved under mild conditions using a low catalyst loading of 0.5 mol%.