312
M. Benaglia
Scheme 5.
immobilized very soon after the first seminal works of List and Barbas,
on both soluble and insoluble supports (Cozzi 2006). Our group developed the first soluble polymer-supported version of proline that was
tested successfully tested in the adirect aldol condensation of ketones
with aldehydes (Benaglia et al. 2001).
The immobilization of (2S,4R)-4-hydroxyproline on PEG 5000 monomethylether (MeOPEG) by means of a succinate spacer created, at very
good yield, the supported catalyst 17.
In the presence of 0.25–0.35 mol equivalents of the catalyst 17, acetone reacted with enolizable and nonenolizable aldehydes in dimethyl
fluoride at room temperature to afford the aldol product in yields (up to
80%) and ee (up to >98%), comparable with those obtained using nonsupported proline derivatives as catalysts (that did, however, give faster
M. Benaglia
Scheme 5.
immobilized very soon after the first seminal works of List and Barbas,
on both soluble and insoluble supports (Cozzi 2006). Our group developed the first soluble polymer-supported version of proline that was
tested successfully tested in the adirect aldol condensation of ketones
with aldehydes (Benaglia et al. 2001).
The immobilization of (2S,4R)-4-hydroxyproline on PEG 5000 monomethylether (MeOPEG) by means of a succinate spacer created, at very
good yield, the supported catalyst 17.
In the presence of 0.25–0.35 mol equivalents of the catalyst 17, acetone reacted with enolizable and nonenolizable aldehydes in dimethyl
fluoride at room temperature to afford the aldol product in yields (up to
80%) and ee (up to >98%), comparable with those obtained using nonsupported proline derivatives as catalysts (that did, however, give faster