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Enantioselective organocatalytic double bonds

The required chiral sulfur ylide of type 59 is formed in a reaction with a diazo compound in the presence of an achiral metal catalyst. Subsequently, asymmetric reaction of the chiral ylide 59 with the C=N double bond of the imine proceeds diastereoselectively and enantioselectively, giving the optically active aziridine 57. The chiral sulfide catalyst released is then used for the next catalytic cycle. The cat-alytically active species in the asymmetric process is the sulfide, so this concept can also be regarded as an organocatalytic reaction. [Pg.119]

The organocatalytic enantioselective reduction of C=C, C=0, and C=N double bonds is a relatively young area for which many new and exciting developments can be expected in the near future. Hantzsch esters are useful organic hydrides, and a recent review has summarized the results obtained to date in organocataly-sis [27]. The case of silicon hydrides is convenient for imine or ketone reductions, as a chiral base can act as an organic catalyst. The asymmetric reductions of ketones catalyzed by oxazaborolidines and pioneered by Itsuno [28] and Corey [29] could not be included in this chapter. [Pg.400]


See other pages where Enantioselective organocatalytic double bonds is mentioned: [Pg.119]    [Pg.397]    [Pg.118]    [Pg.165]    [Pg.122]    [Pg.530]    [Pg.23]    [Pg.1092]    [Pg.1092]    [Pg.137]   
See also in sourсe #XX -- [ Pg.553 ]




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Double enantioselection

Organocatalytic

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