Para-quinone methide: A new player in asymmetric catalysis

This is the accepted version of the following article: Parra, A. and Tortosa, M. (2015), para-Quinone Methide: a New Player in Asymmetric Catalysis. ChemCatChem, 7: 1524–1526, which has been published in final form at http://dx.doi.org/10.1002/cctc.201500176. This article may be used for non-commercial purposes in accordance with the Wiley Self-Archiving Policy wiley.com/WileyCDA/Section/id- 820227.htmlWe thank the European Research Council (ERC-337776) for the financial support. M. T. and A. P. thank MICINN for RyC and JdC contracts, respectivel

Cyclopropyl and cyclobutylboronates and silanes: A stereo­selective approach

Chiral cyclopropyl- and cyclobutylboronic esters and -silanes have become attractive intermediates for the preparation of functionalized small rings. This review highlights the stereoselective methods developed for their preparation, including both diastereo- and enantio­selective approaches. 1 Introduction 2 Stereoselective Synthesis of Cyclopropyl- and Cyclobutylboronates and -silanes 2.1 Diastereoselective Synthesis of Cyclopropyl- and Cyclobutylboronates and -silanes 2.2 Asymmetric Synthesis of Cyclopropyl- and Cyclobutylboronates and -silanes 3 ConclusionsWe thank the European Research Council (ERC-337776) and MINECO (CTQ2016-78779-R) for financial support. M.T. thanks MICINN for a RyC contrac

Regio- and stereospecific copper-catalyzed substitution reaction of propargylic ammonium salts with aryl Grignard reagents

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Journal of the American Chemical Society, copyright © American Chemical Society after peer review. To access the final edited and published work see http://doi.org/10.1021/jacs.7b05273We have developed a copper-catalyzed substitution reaction of propargylic ammonium salts with aryl Grignard reagents. The reaction is stereospecific and α-regioselective and proceeds with exceptional functional group tolerance. Conveniently, a stable, inexpensive, and commercially available copper salt is used and no added ligand is requiredWe thank the European Research Council (ERC-337776) and MINECO (CTQ2016-78779-R) for financial support. M.T. thanks MICINN for a RyC contrac

Copper-catalyzed enantioselective synthesis of β-Boron β-Amino Esters

In this report, the enantioselective, copper-catalyzed borylation of β-amidoacrylates is disclosed. A broad variety of biologically important α-aminoboronates has been prepared with consistently high levels of enantiocontrol using an inexpensive copper catalyst and a commercially available chiral ligand. The method can be applied to the synthesis of novel boron-containing dipeptides and hemiboronatesWe thank the European Research Council (ERC-337776), MINECO (CTQ2016-78779-R), National Science Foundation (1151092 and 1543699) for financial support. M. T. thanks MICINN for RyC contrac

Copper-catalyzed silylation of p-quinone methides: New entry to dibenzylic silanes

An efficient and general copper(i)-catalyzed silylation of p-quinone-methides is described. Non-symmetric dibenzylic silanes are obtained in high yields under mild reaction conditions. These compounds can be used as bench-stable benzylic carbanion precursorsWe thank the European Research Council (ERC-337776) and MINECO (CTQ2012-35957) for financial support. M. T. and A. P. thank MICINN for RyC and JdC contract

Enantioselective synthesis of cyclobutylboronates via a copper-catalyzed desymmetrization approach

This is the peer reviewed version of the following article: Guisán-Ceinos, M., Parra, A., Martín-Heras, V. and Tortosa, M. (2016), Enantioselective Synthesis of Cyclobutylboronates via a Copper-Catalyzed Desymmetrization Approach. Angew. Chem., which has been published in final form at http://dx.doi.org/10.1002/ange.201601976. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.In this report, the first catalytic enantioselective synthesis of cyclobutylboronates, using a chiral copper(I) complex, is disclosed. A broad variety of cyclobutanes have been prepared with consistently high levels of diastereo- and enantiocontrol. Moreover, this method constitutes the first report of an enantioselective desymmetrization of meso-cyclobutenes to prepare chiral cyclobutanesWe thank the European Research Council (ERC-337776) and MINECO (CTQ2012-35957) for financial support. M. T. and A. P. thank MICINN for RyC and JdC contract

Stereoselective traceless borylation–allenation of propargylic epoxides: dual role of the copper catalyst

This is the peer reviewed version of the following article: Chemistry: A European Journal 23.69 (2017): 17478 –17481, which has been published in final form at http://doi.org/10.1002/chem.201705019. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingChiral α-allenols are prepared with high diastereocontrol through an unprecedented and spontaneous β-oxygen elimination of an α-epoxy vinyl boronate. Stochiometric experiments and DFT calculations support a dual role of the copper catalyst, which orchestrates the hydroboration and the syn-elimination stepThe European ResearchCouncil (ERC-337776) and MINECO (CTQ2016-78779-R) for financial support M.T.thanks MICINNfor a RyC contrac

Copper-catalysed cross-coupling of alkyl Grignard reagents and propargylic ammonium salts: Stereospecific synthesis of allenes

Herein we describe a robust and practical method to prepare enantiomerically enriched trisubstituted allenes using alkyl Grignard reagents and bench stable propargylic ammonium salts. Excellent yields as well as regio- and stereoselectivities are observed. Our conditions provide a solution to the allene racemization, which has been a long-standing problem when using Grignard reagents

Insight into the copper-catalyzed borylation of strained alkenes

This document is the accepted manuscript version of a published work that appeared in final form in Synlett 2015; 26(04): 494-500, copyright © Georg Thieme Verlag Stuttgart · New York after peer review and technical editing by the publisher. To access the final online work see DOI: 10.1055/s-0034-1379882The copper-catalyzed hydro- and carboboration of strain alkenes is presented. The reaction is highly diastereoselective and affords boronic ester derivatives many of which are difficult to synthesize by known methods. Competition experiments with different alkenes show that high levels of chemoselectivity can be achieved. DFT calculations are in agreement with the observed chemoselectivityWe thank the European Research Council (ERC-337776) and MINECO (CTQ2012-35957 and CTQ2013-43698-P) for financial support. M. T. and S. D.-T thank MINECO for RyC contracts. A. P. thanks MINECO for JyC contrac

Base-Induced Sulfoxide-Sulfenate Rearrangement of 2-Sulfinyl Dienes for the Regio- and Stereoselective Synthesis of Enantioenriched Dienyl Diols

The base-induced [2,3]-sigmatropic rearrangement of a series of enantiopure 2-sulfinyl dienes has been examined and optimized using a combination of NaH and iPrOH. The reaction takes place by allylic deprotonation of the 2-sulfinyl diene to give a bis-allylic sulfoxide anion intermediate that after protonation undergoes sulfoxide-sulfenate rearrangement. Different substitution at the starting 2-sulfinyl dienes has allowed us to study the rearrangement finding that a terminal allylic alcohol is determinant to achieve complete regioselectivity and high enantioselectivities (90:10-95:5) with the sulfoxide as the only element of stereocontrol. Density functional theory (DFT) calculations provide an interpretation of these resultsThe authors thank MICINN (PID2019-107380GB-I00) for financial support. M.M. thanks Erasmus+ program for an internship. The authors thank Paula López and Fernando Romero for their initial experiments with compounds 8, 9, and 11. They also thank the Centro de Computación Científica at the UAM for their generous allocation of computer tim