01351nas a2200157   4500008004100000245008900041210006900130260000800199300001600207490000700223520079000230100002201020700001701042700001901059856011501078       2011                        eng d00aExtending nhc-catalysis: reaction of aldehydes with unconventional reaction partners0 aExtending nhccatalysis reaction of aldehydes with unconventional  cJUL  a1182–11950 v443 a<p>Transition metal catalysis is a powerful means of effecting organic reactions, but it has some inherent drawbacks, such as the cost of the catalyst and the toxicity of the metals. Organocatalysis represents an attractive alternative and, in some cases, offers transformations unparalleled in metal catalysis. Unique transformations are a particular hallmark of N-heterocyclic carbene (NHC) organocatalysis, a versatile method for which a number of modes of action are known. The NHC-catalyzed umpolung (that is, the inversion of polarity) of electrophilic aldehydes, through formation of the nucleophilic Breslow intermediate, is probably the most important mode of action. In this Account, we discuss the reaction of Breslow intermediates with unconventional reaction partners.</p>1 aBiju, Akkattu, T.1 aKuhl, Nadine1 aGlorius, Frank  uhttps://library.ncl.res.in/content/extending-nhc-catalysis-reaction-aldehydes-unconventional-reaction-partners