Ytterbium reagents

Nakagawa and coworkers reported a chiral ytterbium catalyst 34 which was prepared from l,l -(2,2 -bisacylamino)binaphthalene and Yb(OTf)3 in the presence of diisopro-pylethylamine by a method similar to that used for Kobayashi s chiral ytterbium reagent [52] (Scheme 1.65, Table 1.66). The amine also plays an important role in this reaction, because racemic cycloadducts were obtained without the tert-amine. Reduc-... 

How can we generate an even more versatile Lewis-acid catalyst This is probably the ultimate goal of synthetic chemists. The recently developed chemistry of lanthanide catalysts, for example, scandium and ytterbium reagents, might be one recent achievement in this field. The catalyst can even be used in the aqueous phase — obviously not possible with classical Lewis-acid reagents [8]. 

Other organolanthanide reagents are covered in Chapter 1.10 in this volume, while selective carbonyl addition reactions pr< noted by samarium and ytterbium reagents are surveyed in Chapter 1.9. 

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