Enantioselective Intramolecular C–H Insertion Reactions of Donor–Donor Metal Carbenoids

Abstract

The first asymmetric insertion reactions of donor–donor carbenoids, i.e., those with no pendant electron-withdrawing groups, are reported. This process enables the synthesis of densely substituted benzodihydrofurans with high levels of enantio- and diastereoselectivity. Preliminary results show similar efficiency in the preparation of indanes. This new method is used in the first enantioselective synthesis of an oligoresveratrol natural product (E-δ-viniferin).

Total Synthesis of Viniferifuran, Resveratrol‐Piceatannol Hybrid, Anigopreissin A and Analogues – Investigation of Demethylation Strategies

“…These impressive studies spawned a number of syntheses applying innovative approaches for the preparation of racemic compounds 5,6. The first enantiototal synthesis of a stilbene dimer was the case of δ‐viniferin ( 3 ) where Shaw and co‐workers elegantly applied a carbene‐insertion chemistry using a rhodium catalyst to construct the dihydrobenzofuran core asymmetrically 7. Our interest in this intriguing family of natural products stems from the finding that the resveratrol tetramer (−)‐hopeaphenol blocks type III secretion, an indispensable virulence system, in the Gram‐negative pathogens Yersinia pseudotuberculosis and Pseudomonas aeruginosa 8.…”

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

“…The possibility to regenerate a functionalized resin by simple washing with aqueous KI 3 /KOH solution makes the process more sustainable. This method produces KI solution as waste, and it is an alternative way for the direct oxidation of hydrazones, that often requires the use of heavy metals such as HgO, Pb(OAc) 4 and AgO [82–83]. …”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…Other processes emanating from tosylhydrazones that likely involve carbene complex intermediates include: (1) arylative dearomatization of furancarboxaldehyde tosylhydrazones containing pendant alcohol groups [1154]; (2) N-vinylation of indoles and carbazoles through palladium catalyzed coupling of the N-H compounds with diazo compounds [1155]; (3) a DFT study of palladium-catalyzed preparation of 1,2,4-trienes from propargylic carboxylates and tosylhydrazones [1156]; and (4) enantioselective intramolecular C-H insertions using hydrazone-derived copper carbenoids [1157]. presented.…”