Corrigendum: Iron- and Bismuth-Catalyzed Asymmetric Mukaiyama Aldol Reactions in Aqueous Media

Abstract

The authors found that sentences were corrupted and the cited references were incomplete in the second paragraph of the Introduction. This paragraph should read as follows. In Scheme 5, the compound in the middle of the 4th row should be labeled 3 te. In Scheme 6, 1 u and 3 ua should read 1 v and 3 va, respectively. The authors apologize for these mistakes. Catalytic asymmetric variants on the Mukaiyama aldol reaction were initiated by a report on chiral tin(II) Lewis acid-catalyzed reactions in 1990,3 and chiral boron,4 chiral titanium,5 and chiral zirconium6 Lewis acids followed. Since then, many chiral Lewis acids have been developed to target asymmetric Mukaiyama aldol reactions.7 On the other hand, “direct-type aldol reactions” have been reported, in which the reactions did not proceed through silicon enolates but rather through ketones or synthetic equivalents, which reacted as nucleophiles directly with aldehydes.8, 9 While silicon enolates have to be prepared (isolated) from ketones using stoichiometric amounts of bases and silicon sources in Mukaiyama aldol reactions, direct-type reactions give aldol adducts directly. Therefore, from an atom economical point of view, the latter has an advantage. At the present stage, however, nucleophiles that can be used in direct-type aldol reactions are limited to ketones and aldehydes in most cases.10 Furthermore, among them there are few examples of aromatic ketones or acyclic ketones using non-metal catalysts.11 Silicon enolates that can be applied to the Mukaiyama aldol reaction are derived not only from ketones and aldehydes but also from esters, amides, lactones, lactams, enones, unsaturated esters, unsaturated amides, and others. Therefore, from the standpoint of substrate generality, the Mukaiyama aldol reaction still has an advantage over the direct-type aldol reaction.