Lanthanides in organic synthesis: Eu+3-catalyzed Michael addition of 1,3- dicarbonyl compounds

Easy approach to chiral Michael adducts by Eu+3‐catalyzed conjugate addition

“…In connection with our previous research 16,17 that disclosed the unprecedented capability of Eu +3 derivatives to promote the efficient Michael addition of active methylene compounds, as linear and cyclic ␤-ketoesters, ␤-diketones, etc., we decided to investigate the reactivity of (4S)-Nacetoacetyl-4-benzyloxazolidin-2-one 1a, 18 and (4R)-Nacetoacetyl-4-phenyloxazolidin-2-one 1b 19 as chiral donors in the presence of easily available Eu +3 catalysts.…”

Recent developments in lanthanide mediated organic synthesis

“…367 Catalytic Lewis acid activation of the carbonyl group by lanthanide salts has been used to effectively promote, amongst others, glyoxalate ene reactions, 368 oxazoline formation from esters, 369 Michael reactions, 370 Tishchenko reductions of β-hydroxy ketones, 371 and Baeyer-Villiger oxidations. 372 In the last of these, related to Barrett's observations, TfOH is also capable of the same acceleration but, in contrast to the use of Sc(OTf ) 3 , rigorously anhydrous conditions are required. 373 The aldol reaction continues to be an active area for lanthanide catalysis.…”

Recent Advances in Catalytic Enantioselective Michael Additions

“…(Tomioka, 1997 83 ) L46 (Toke, 1995 82 ) L47 (Toke, 1998 82 ) (S)-L49 (Yamaguchi, 1993 84,85 mentioned in the preceeding chapters, the race for a "universal" catalytic system applicable to a broad range of Michael donors and acceptors is still open. Thus, many efforts towards this goal have been devoted employing different metals, e.g., Sn-, 86 Zn-, 87 La-, 88 and Ti-catalysis. 89 However, only the titanium-BINOL complex (R)-L50 presented by Mukaiyama et al 89a afforded the Michael adduct of the silyl enol ether 22e and cyclopent-2-en-1-one (1f) with high selectivity (90% ee, Scheme 50).…”