Miscellaneous Domino Reactions

these authors reported the synthesis of chiral cis-l,3,4-trisubstituted cyclopentenes based on an enantioselective N-heterocyclic carbene-catalyzed domino annulation of a,p-unsaturated aldehydes and 4-oxoenoates [236]. The domino products were achieved in low to high yields (25-93%), in moderate to 

On the basis of the proposed catalytic cycle, aldehyde 9 reacts with 1,3-indandione 178 by amine-catalyzed Knoevenagel condensation to provide the benzylidene-indandione B via iminium ion A, which is an excellent organic Lewis acid. This intermediate thns undergoes a Diels-Alder or a double Michael reaction with the soft nucleophile 2-amino-1,3-butadiene C generated in situ from enone 84 and the amine catalyst to produce the 

SCHEME 2.54 Trisubstituted cyclohexane derivatives 170 via quadruple cascade reaction. 

The same group reported an organocatalytic diastereo-specific and enantioselective domino Knoevenagel/Diels-Alder procedure to obtain highly substituted spiro[5,5] 

SCHEME 2.55 Enders s Friedel-Crafts-type/Michael/Michael/Aldol condensation domino sequence. 

1-dioxides with allenes by using (i ,i )-i-Pr-FOXAP as ligand. 

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I 37 Formation of 3-, 4- and 5-Membered Cycles by Intermolecular Reactions yi.2.2.2 Miscellaneous Domino Reactions... 

Given the generality of the MBFT concept, only a few examples of organocatalyzed reactions are highlighted in this section, including some miscellaneous organocatalyzed reactions and domino reactions. As much as possible, relevant applications of these reactions are also discussed. 

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