A novel carbonyl alkynylation has been accomplished based on utilization of the Meerwein-Ponndorf-Verley (MPV) reaction system. The success of the MPV alkynylation crucially depends on the discovery of the remarkable ligand acceleration effect of 2,2'-biphenol. For example, the alkynylation of chloral (2c) with the aluminium alkoxide 6(R = Ph), prepared in situ from Me(3)Al, 2,2'-biphenol and 2-me
The enantioselective catalytic alkynylation of aromatic aldehydes is reported using a sterically highly hindered bis-cyclometalated rhodium-based Lewis acid catalyst featuring the octahedral metal as the only stereogenic center. Yields of 58–98% with 79–98% enantiomeric excess were achieved using 1–2 mol % of catalyst. This work complements previous work from our laboratory on the enantioselective alkynylation