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Recent Advances in Transition Metal-Catalysed Hydroacylation of Alkenes and Alkynes Avipsa Ghosh Iowa State University

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Recent Advances in Transition Metal-Catalysed Hydroacylation of Alkenes and Alkynes Avipsa Ghosh Iowa State University Chemistry Publications Chemistry 2016 Recent advances in transition metal-catalysed hydroacylation of alkenes and alkynes Avipsa Ghosh Iowa State University Kirsten F. Johnson Iowa State University Kevin L. Vickerman Iowa State University, [email protected] James A. Walker Jr. Iowa State University Levi M. Stanley Iowa State University, [email protected] Follow this and additional works at: https://lib.dr.iastate.edu/chem_pubs Part of the Organic Chemistry Commons The ompc lete bibliographic information for this item can be found at https://lib.dr.iastate.edu/ chem_pubs/1041. For information on how to cite this item, please visit http://lib.dr.iastate.edu/ howtocite.html. This Article is brought to you for free and open access by the Chemistry at Iowa State University Digital Repository. It has been accepted for inclusion in Chemistry Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Recent advances in transition metal-catalysed hydroacylation of alkenes and alkynes Abstract This highlight discusses developments in transition metal-catalysed alkene and alkyne hydroacylation reactions over the past three years. The discussion summarizes the development of new catalyst systems for alkene and alkyne hydroacylation and applications to the synthesis of important ketone building blocks. The highlight captures transition metal-catalysed alkene and alkyne hydroacylation at a time of impressive growth when cobalt, nickel, ruthenium, and iridium catalysts are emerging as complements or replacements for traditional rhodium catalysts. Disciplines Chemistry | Organic Chemistry Comments This article is published as Ghosh, Avipsa, Kirsten F. Johnson, Kevin L. Vickerman, James A. Walker, and Levi M. Stanley. "Recent advances in transition metal-catalysed hydroacylation of alkenes and alkynes." Organic Chemistry Frontiers 3, no. 5 (2016): 639-644. doi: 10.1039/C6QO00023A. Posted with permission. Creative Commons License This work is licensed under a Creative Commons Attribution 3.0 License. This article is available at Iowa State University Digital Repository: https://lib.dr.iastate.edu/chem_pubs/1041 ORGANIC CHEMISTRY FRONTIERS View Article Online HIGHLIGHT View Journal | View Issue Recent advances in transition metal-catalysed hydroacylation of alkenes and alkynes Cite this: Org. Chem. Front., 2016, 3, 639 Avipsa Ghosh, Kirsten F. Johnson, Kevin L. Vickerman, James A. Walker, Jr. and Levi M. Stanley* This highlight discusses developments in transition metal-catalysed alkene and alkyne hydroacylation reactions over the past three years. The discussion summarizes the development of new catalyst systems Received 15th January 2016, for alkene and alkyne hydroacylation and applications to the synthesis of important ketone building Accepted 11th February 2016 blocks. The highlight captures transition metal-catalysed alkene and alkyne hydroacylation at a time of DOI: 10.1039/c6qo00023a impressive growth when cobalt, nickel, ruthenium, and iridium catalysts are emerging as complements or rsc.li/frontiers-organic replacements for traditional rhodium catalysts. Creative Commons Attribution 3.0 Unported Licence. Introduction Transition metal-catalysed alkene and alkyne hydroacylation, the formal addition of an aldehyde C–H bond across an un- Department of Chemistry, Iowa State University, Ames, IA 50011, USA. saturated C–C bond, has emerged as a powerful, catalytic – E-mail: [email protected] process to synthesize ketones over the past four decades.1 3 The identification and development of new catalysts has greatly expanded the scope and synthetic utility of these hydro- This article is licensed under a Levi Stanley received his B.A. in acylation reactions in recent years. Intramolecular alkene chemistry from Augustana hydroacylation reactions are now well-established methods to College (SD) in 2001, and he synthesize carbocyclic and heterocyclic ketones, often with Open Access Article. Published on 11 February 2016. Downloaded 8/1/2018 11:43:04 PM. received his Ph.D. from North high enantioselectivities. In addition, the development of Dakota State University in 2007 intermolecular hydroacylations of new combinations of under the supervision of Pro- alkenes and alkynes with aldehydes continues to rapidly fessor Mukund P. Sibi. After post- expand and provide direct routes to new ketones from simple Avipsa Ghosh, doctoral studies at the University starting materials. Kevin L. Vickerman, of Illinois at Urbana-Champaign Despite recent advances in catalytic alkene and alkyne Kirsten F. Johnson, with Professor John Hartwig, he hydroacylation reactions, many challenges remain to fully James A. Walker Jr., joined the faculty at Iowa State harness the synthetic potential of these valuable processes. Levi M. Stanley University in 2012 as an assist- These challenges include: intramolecular hydroacylations to (from left to right). ant professor in the Department form medium and large rings in the absence of functional of Chemistry. Kirsten Johnson received her B.S. in chemistry and groups to stabilize catalytic intermediates; intermolecular Spanish from the University of Wisconsin – Madison in 2011. hydroacylations that encompass a much broader array of sub- Avipsa Ghosh received her B.Sc. in chemistry from the University strates; and new catalyst types that improve activity, comp- of Calcutta in 2006, and she received her M.Sc. in organic chem- lement the selectivity, and reduce the cost of widely studied istry from Bangalore University in 2008. Kevin Vickerman received rhodium complexes of bisphosphine ligands. his B.S. in chemistry and cellular and molecular biology from Since the initial report by Sakai and co-workers in 1972,4 Winona State University in 2013. James Walker received his B.S. hydroacylation of alkenes and alkynes has evolved to en- in chemistry from the University of Cincinnati in 2012. Johnson, compass reactions catalysed by not only transition metal Ghosh, Vickerman, and Walker are currently pursuing Ph.D. complexes, but also N-heterocyclic carbenes (NHCs)5,6 and – studies in chemistry at Iowa State University with Prof. Levi photocatalysts.7 9 This highlight will focus on recent develop- Stanley. Their research is focused on the development of new cata- ments in transition metal-catalysed alkene and alkyne hydro- lytic alkene and alkyne hydroacylation reactions. acylation reactions over the past three years. The discussion is This journal is © the Partner Organisations 2016 Org. Chem. Front.,2016,3,639–644 | 639 View Article Online Highlight Organic Chemistry Frontiers divided by catalyst type and includes highlights of rhodium-, cobalt-, ruthenium-, iridium-, and nickel-catalysed processes. Rhodium-catalysed alkene and alkyne hydroacylation Since the initial report of transition metal-catalysed olefin hydroacylation,4 rhodium-catalysed alkene and alkyne hydro- acylation reactions have remained at the forefront of studies in the area. While much progress has been made in the develop- Scheme 2 Intermolecular hydroacylation of internal alkenes with ment of alkene and alkyne hydroacylation reactions with β-substituted aldehydes. aldehydes containing functional groups capable of coordinat- ing the rhodium center, intermolecular alkene hydroacyla- tions with simple aromatic and aliphatic aldehydes remain increasing the rate of olefin insertion in to the rhodium challenging. hydride bond, which prevents decarbonylation by maintaining Dong and co-workers recently reported highly branched- a low concentration of the acyl hydride intermediate. This cata- selective intermolecular hydroacylation reactions of a variety of lyst system enables hydroacylations of a range of both 1,1- and non-chelating aliphatic, aromatic, and alkenyl aldehydes 1,2-disubstituted alkenes, including cycloalkenes, cyclic and with ortho-vinylphenols (Scheme 1).10,11 [Rh(cod)(OMe)] and 2 acyclic vinyl ethers, and α,β-unsaturated esters, with aryl and a small-bite-angle bisphosphine ligand, bis(dicyclohexyl- non-aryl aldehydes. phosphino)methane (dcpm), combine with the ortho-vinyl- Inspired by Tanaka and Suemune’s report on desymmetri- Creative Commons Attribution 3.0 Unported Licence. phenol substrate to generate an electron-rich and neutral rhodium zation of β-bis(alkenyl)aldehydes to generate cyclopentanones complex that has a lower barrier for the turnover-limiting, bearing β-quaternary stereogenic centers,15,16 Dong and non-directed oxidative addition of Rh to the aldehyde C–H coworkers developed an enantioselective desymmetrization of bond. This catalyst promotes reactions of an array of non- α-trisubstituted aldehydes to form cyclopentanones with chelating aldehydes with a wide range of substituted ortho-vinyl- α-quaternary stereogenic centers (Scheme 3).17 A catalyst gener- phenols to form branched ketone products (typically >20 : 1 ated in situ from [Rh(coe) Cl] ,(R)-DTBM-MeO-BIPHEP and – α 2 2 selectivity) in 50 99% yield. The -aryl ketone products can α AgBF4 facilitates the desymmetrization of the -quaternary readily undergo acid-catalyzed cyclocondensation to form center through an isomerization–hydroacylation cascade. Key benzofurans in high yields. – This article is licensed under a to this isomerization hydroacylation cascade is a rare endo- Development in the Willis and Weller labs of catalysts con- cyclic β-hydride elimination for which this study provides taining small-bite-angle bisphosphine ligands with the general experimental evidence that supports
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