F rigid cats: The power of conformationallystabilizedcatalysts is demonstrated. By taking appropriate advantage of fluorineinsertion (see scheme), purely conformationalcatalyst design led to a notable improvement in enantioselectivities from around 70 % to 91–98.5 % ee. The other advantage of this approach is the better understanding of the origin of the stereoselectivity in the given catalytic
Asymmetric addition of α-hetero-disubstituted aldehydes to vinyl sulfones; formation of highly functionalized tetrasubstituted carbon centres
作者:Adrien Quintard、Alexandre Alexakis
DOI:10.1039/c000326c
日期:——
Aminalâpyrrolidine catalysed addition of α-hetero-disubstituted aldehydes to vinyl sulfones is described in high enantioselectivity (ee up to 97%). The obtained adducts can easily be converted to enantioenriched synthons as for example 2,2-dialkylepoxide. Evidence for a kinetic resolution is also observed.