Catalytic Enantioselective Trapping of an Alcoholic Oxonium Ylide with Aldehydes: Rh^II/Zr^IV‐Co‐Catalyzed Three‐Component Reactions of Aryl Diazoacetates, Benzyl Alcohol, and Aldehydes

Abstract

The right combination: A catalytic asymmetric multicomponent reaction has been developed in which two stereogenic carbon centers are constructed in a single step (see scheme; erythro/threo 90:10, up to 80 % yield, 98 % ee). This type of enantioselective three‐component reaction generates α,β‐dihydroxy acid derivatives in good yields and with excellent enantioselectivities. Bn=benzyl.

Vinyl Esters as Acetaldehyde Surrogates: Potential Utility in Some Common Multicomponent Sequences

“…Unfortunately, Use of acetaldehyde (and sometimes other aliphatic aldehydes) in many MCRs is not always as straightforward as that of aromatic aldehydes. There are plentiful reports where many common MCR sequences either failed or resulted in lower yield of products when attempted with acetaldehyde /aliphatic aldehydes . This may be due to their different reactivity profile than aromatic aldehydes, higher sensitivity towards self‐polymerization, low stability and competitive isomerisation of the resultant imine (with an amine) to an enamine.…”

Copper(II)‐catalyzed Domino Reaction of the Acyclic Ketene‐(S,S)‐Acetals with Diazo Compounds: Convenient Synthesis of Poly‐substituted Thiophenes

“…[9] In particular, transition-metalcatalyzed reactions of diazo compounds have been highly successful. [11,12] In addition, the situ-generation of sulfur ylides from diazo compounds and sulfide has been well documented for the construction of CÀ S and CÀ C bond [13,14] via the Doyle-Kirmse [15] or Stevens [16] rearrangement reaction. [11,12] In addition, the situ-generation of sulfur ylides from diazo compounds and sulfide has been well documented for the construction of CÀ S and CÀ C bond [13,14] via the Doyle-Kirmse [15] or Stevens [16] rearrangement reaction.…”

“…Screening of copper catalysts revealed that Cu(OTf) 2 was optimal one (entries [2][3][4][5]. Solvent effects have also been observed, and the reaction proceeded well in DCE, while DMF, THF and CH 3 CN are not suitable for this reaction (Table 1, entries [12][13][14]. Solvent effects have also been observed, and the reaction proceeded well in DCE, while DMF, THF and CH 3 CN are not suitable for this reaction (Table 1, entries [12][13][14].…”

“…[10] Pioneered by Doyle and Hu, the applications of electrophilic trapping in situ-generated ylides from metal carbene have become a versatile and useful synthetic strategy for the rapid construction of complex molecules in recent decade. [11,12] In addition, the situ-generation of sulfur ylides from diazo compounds and sulfide has been well documented for the construction of CÀ S and CÀ C bond [13,14] via the Doyle-Kirmse [15] or Stevens [16] rearrangement reaction. In stark contrast, little attention has been paid to cleavage CÀ S bond [17] via sulfur ylide to produce thiophenes.…”

Trapping of Oxonium Ylides with Michael Acceptors: Highly Diastereoselective Three-Component Reactions of Diazo Compounds with Alcohols and Benzylidene Meldrum’s Acids/4-Oxo-enoates

“…We initiated our study by examining the reaction of methyl phenyldiazoacetate, benzyl alcohol, and readily available methyl cinnamate (1a) in the presence of Rh 2 (OAc) 4 in CH 2 Cl 2 at 25°C. 8 Unfortunately, no desired three-component product was observed, instead only a traditional O-H insertion of the diazo compound into benzyl alcohol took place.…”