Reaction of aromatic aldehydes and ketones with ytterbium metal gives the corresponding pinacols in high yields. Cross-coupling reaction of benzophenone with other carbonyl compounds to produce unsymmetrical pinacols is also described.
corresponding unsymmetrical 1,2-diols in moderate to good yields. α-Hydroxy ketones were prepared by the lanthanum metal-assistedreaction of diaryl ketones with esters or nitriles, followed by hydrolysis with aq HCl. It is interesting to note that for the epoxides, the coupling reaction proceeded via the Meinwald rearrangement of epoxides to give the corresponding 1,2-diols.
Regioselective Organocatalytic Formation of Carbamates from Substituted Cyclic Carbonates
作者:Sergio Sopeña、Victor Laserna、Wusheng Guo、Eddy Martin、Eduardo C. Escudero-Adán、Arjan W. Kleij
DOI:10.1002/adsc.201600290
日期:2016.6.30
A highlyregioselective catalytic approach has been developed towards carbamates derived from cyclic organic carbonates by reaction of the latter with amine reagents under organocatalytic control. For various combinations of carbonate and amine substrates, an organocatalyst (TBD: 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene) was used to increase the reaction kinetics while exerting excellent regioselective control
Retropinacol/Cross-Pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols
作者:Ulf Scheffler、Reinhard Stößer、Rainer Mahrwald
DOI:10.1002/adsc.201200358
日期:2012.10.8
A new concept to access unsymmetrical 1,2-diols with high yields is reported. This new methodology is based on a retropinacol/cross-pinacol coupling process. This transformation is characterized by its operational simplicity and very mild reaction conditions.