N-Heterocyclic Carbene Organocatalysts for Dehydrogenative Coupling of Silanes and Hydroxyl Compounds
作者:Dongjing Gao、Chunming Cui
DOI:10.1002/chem.201301893
日期:2013.8.19
Go organic! N‐Heterocyclic carbene (NHC) 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene (IiPr) has been found to be an efficient and selective catalyst for the dehydrogenativecoupling of a wide range of silanes and hydroxyl groups to form SiO bonds under mild and solvent‐free conditions (see scheme). Mechanistic studies indicated that the activation of hydroxyl groups by the NHC is the most plausible
Enantio- and Diastereoselective Synthesis of Substituted Tetrahydro-1<i>H</i>-isochromanes through a Dynamic Kinetic Resolution Proceeding under Dienamine Catalysis
作者:Ane Orue、Efraím Reyes、Jose L. Vicario、Luisa Carrillo、Uxue Uria
DOI:10.1021/ol301602h
日期:2012.7.20
nes react with enolizable α,β-unsaturatedaldehydes in the presence of a chiral secondary amine catalyst furnishing a wide range of differently substituted tetrahydro-1H-isochromanes with excellent results. The reaction relies on the activation of the enal by the catalyst through the formation of a dienamine intermediate, which undergoes a Diels–Alder/elimination cascade reaction. Moreover, the overall
Organocatalytic Enantioselective α-Hydroxymethylation of Aldehydes: Mechanistic Aspects and Optimization
作者:Robert K. Boeckman、Kyle F. Biegasiewicz、Douglas J. Tusch、John R. Miller
DOI:10.1021/acs.joc.5b00380
日期:2015.4.17
Further studies of the direct enantioselective α-hydroxymethylation of aldehydes employing the α,α-diarylprolinol trimethylsilyl ether class of organocatalysts are described. This process has proven efficient for access to β-hydroxycarboxylic acids and δ-hydroxy-α,β-unsaturated esters from aldehydes in generally good yields, excellent enantioselectivity, and compatibility with a broad range of functional