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Abstract
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Organocatalyst trityl chloride (Ph
CCl), by in situ formation of trityl carbocation with
inherent instability, ef?ciently promotes the cross-aldol condensation reaction between
cycloalkanones and arylaldehydes in solvent-free and homogeneous media to afford a,a
transformations based on new reactivity concepts have
been identi?ed, often with no counterpart in the more
established catalysis regimens [1–9]. Triarylmethyl chlorides
(Ar
CCl) are an attractive class of small-molecule
organocatalysts, which have been utilized to promote a few
3
organic transformations by in situ formation of triarylmethyl
carbocations [6–9]. It is noteworthy that the
inherent instability of carbocations has precluded up to
now their use in catalysis with decent turnover numbers [7].
The aldol condensation reaction has been widely
applied for carbon–carbon bond formation in organic
synthesis [10–12]. Among them, the cross-aldol condensation
of cycloalkanones with arylaldehydes leading to
a,a
0
3
bis(arylidene)cycloalkanones
in high yields. Moreover, an attractive and plausible
mechanism based on observations and the literature is proposed for the reaction.
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