Iodane-Guided ortho C-H Allylation

Wei W Chen; Anton Cunillera; Dandan Chen; Sébastien Lethu; Albert López de Moragas; Jun Zhu; Miquel Solà; Ana B Cuenca; Alexandr Shafir

doi:10.1002/anie.202009369

Iodane-Guided ortho C-H Allylation

Angew Chem Int Ed Engl. 2020 Nov 2;59(45):20201-20207. doi: 10.1002/anie.202009369. Epub 2020 Sep 1.

Authors

Wei W Chen^{1

2}, Anton Cunillera¹, Dandan Chen^{3

4}, Sébastien Lethu⁵, Albert López de Moragas², Jun Zhu⁴, Miquel Solà³, Ana B Cuenca², Alexandr Shafir¹

Affiliations

¹ Dept. of Biological Chemistry, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), c/Jordi Girona 18-26, 08034, Barcelona, Spain.
² Dept. of Organic and Pharmaceutical Chemistry, Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta 390, 08017, Barcelona, Spain.
³ Institute of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, C/ M. Aurèlia Capmany, 69, 17003, Girona, Catalonia, Spain.
⁴ State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
⁵ Institute of Chemical Research of Catalonia, BIST, Avda. Països Catalans 16, 43007, Tarragona, Spain.

PMID: 32721056
DOI: 10.1002/anie.202009369

Abstract

A metal-free C-H allylation strategy is described to access diverse functionalized ortho-allyl-iodoarenes. The method employs hypervalent (diacetoxy)iodoarenes and proceeds through the iodane-guided "iodonio-Claisen" allyl transfer. The use of allylsilanes bearing electron-withdrawing functional groups unlocks the functionalization of a broad range of substrates, including electron-neutral and electron-poor rings. The resulting ortho-allylated iodoarenes are versatile building blocks, with examples of downstream transformation including a concise synthesis of the experimental antimitotic core of Dosabulin. DFT calculations shed additional light on the reaction mechanism, with notable aspects including the aromatic character of the transition-state structure for the [3,3] sigmatropic rearrangement, as well as the highly stereoconvergent nature of the trans-product formation.

Keywords: C−H functionalization; allylic compounds; arenes; hypervalent compounds; rearrangements.

Publication types

Research Support, Non-U.S. Gov't