Carbonyl compounds Morita-Baylis-Hillman derivatives

The aza-Morita-Baylis-HiUman reaction is known to be a useful and atom-economical C-C bond-forming reaction of electron-deficient alkenes with imines usually catalyzed by Lewis bases [202]. It formally involves a sequence of reactions including a Michael addition, a Mannich reaction, a proton transfer, and a retro-Michael reaction ( -elimination). Although there are many reports in the field of the enantioselective aza-Morita-Baylis-Hilhnan reaction, only rare examples of asymmetric domino reactions initiated by this reaction have been reported. In 2010, Sasai et al. [203] developed the first organocatalyzed asymmetric domino aza-Morita-Baylis-Hillman/aza-Michael reaction of a,p-unsaturated carbonyl compounds with N-tosylimines, allowing an easy access to chiral cis-1,3-disubstituted isoindolines as single diastereomers. The process was induced by a Hg-BINOL-derived catalyst and provided these products in high yields and enantioselectivities, as shown in Scheme 10.18. 

Phosphonium salts may be intermediates in different reactions. The Morita-Baylis-Hillman reaction follows such a protocol. In a typical reaction sequence, a,P-unsaturated carbonyl compounds react with aldehydes in the presence of nucleophiles, such as a trialkylphosphine, to afford aldol-like products (Scheme 75/1), while in another example, unsaturated carbonyl compounds with bromo atom at the end of the chain are cyclized to cycloalkene derivatives (Scheme 75/2). In both... 

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