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

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

Enantiospecific Synthesis of 1,3-Disubstituted Allenes from Propargylic Carbonates through a Borylation-1,2-Elimination Process

An array of enantioenriched vinyl boronates bearing an allylic carbonate moiety have been prepared through selective hydroboration of propargyl carbonates. Treatment of these vinyl boronates with TBAF in THF affords enantioenriched 1,3- disubstituted allenes through a novel 1,2-anti elimination in good yields and high enantiospecificitiesWe thank MINECO (CTQ2016-78779-R) and MICINN (PID2019-107380GB I00) for financial suppor

Nuevas reacciones de borilación catalizadas por cobre en la síntesis de boranatos dibencílicos y alenos

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid. Facultad de Ciencias. Departamento de Química Orgánica. Fecha de lectura: 16-07-2018Esta tesis tiene embargado el acceso al texto completo hasta el 16-01-202

Selective Reductive Dimerization of CO 2 into Glycolaldehyde

International audienceThe selective dimerization of CO2 into glycolaldehyde is achieved in a one-pot two-step process via formaldehyde as a key intermediate. The first step concerns the iron-catalyzed selective reduction of CO2 into formaldehyde via formation and controlled hydrolysis of a bis(boryl)acetal compound. The second step concerns the carbene-catalyzed C–C bond formation to afford glycolaldehyde. Both carbon atoms of glycolaldehyde arise from CO2 as proven by the labeling experiment with 13CO2. This hybrid organometallic/organic catalytic system employs mild conditions (1 atm of CO2, 25 to 80 °C in less than 3 h) and low catalytic loadings (1 and 2.5%, respectively). Glycolaldehyde is obtained in 53% overall yield. The appealing reactivity of glycolaldehyde is exemplified (i) in a dimerization process leading to C4 aldose compounds and (ii) in a tri-component Petasis–Borono–Mannich reaction generating C–N and C–C bonds in one process

CO 2 Hydroboration: Impact of the Boryl Moieties on the Reactivity of Four Bis(boryl)acetal Compounds toward 2,6‐Diisopropylaniline

International audienceThe hydroboration of CO2 into bis(boryl)acetal (BBA) compounds is an important transformation, since it enabled to selectively reduce CO2 by 4e- and to subsequently use the BBA compounds as C1 and Cn sources. However, the influence of the nature of the boryl moieties on the reactivity of BBA compounds has not been evaluated so far. In the present study, four BBA compounds – including two new ones – were reacted with 2,6-diisopropylaniline to afford the expected imine. Significant differences in the rate of the reaction from minutes to weeks have been observed depending on the BBA used, showing the importance of the nature of the boryl moieties. Theoretical investigations enabled to propose a mechanism involving the addition of the aniline to the BBA as the rate-determining step and to determine that the steric hindrance of the BBA compounds is the main factor driving the rate of this condensation reaction

Copper-Catalyzed Borylative Aromatization of <i>p</i>‑Quinone Methides: Enantioselective Synthesis of Dibenzylic Boronates

In this report, we establish that DM-Segphos copper­(I) complexes are efficient catalysts for the enantioselective borylation of <i>para</i>-quinone methides. This method provides straightforward access to chiral monobenzylic and dibenzylic boronic esters, with enantiomeric ratios up to 96:4, using a commercially available chiral phosphine. Standard manipulations of the C–B bond afford a variety of chiral diaryl derivatives

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