Enantioselective α-Amination of Branched Aldehydes Promoted by Simple Chiral Primary Amino Acids

Abstract

A series of simple chiral primary amino acids were first successfully applied to promote the enantioselective α-amination of branched aldehydes with azadicarboxylates and the desired adducts bearing quaternary stereogenic centers were obtained in excellent yields (up to 99%) and enantioselectivities (up to 97% ee).

Construction of Quaternary Stereocenters: Asymmetric α‐Amination of Branched Aldehydes Catalyzed by Monoimide Substituted Cyclohexane‐1,2‐Diamines

“…On the other hand, our group is interested in developing new methods to construct substituted amino aldehydes and successfully applied chiral thioureas, amino acids in the amination of aldehydes with excellent results. 16, 18, 15j Based on these achievements and our continuing interests in asymmetric synthesis promoted by chiral amine catalysis, herein we report the asymmetric α‐amination of branched aldehydes with azodicarboxylates catalyzed by simple chiral imide monosubstituted 1,2‐diamine derivatives in excellent enantioselectivities.…”

“…After that, an ion pair catalyst of 9‐amino(9‐deoxy)epi‐quinine and (‐)‐CSA was applied in this transformation . And in 2011, our group disclosed that the simple primary amino acid of 3‐(1‐naphthyl) alanine may catalyze the amination of branched aldehydes with high enantioselectivities . Even so the direct enantioselective preparations of unnatural chiral α‐amino acids, especially chiral quaternary amino acids, are still challenges.…”

“…17 And in 2011, our group disclosed that the simple primary amino acid of 3-(1-naphthyl) alanine may catalyze the amination of branched aldehydes with high enantioselectivities. 18 Even so the direct enantioselective preparations of unnatural chiral a-amino acids, especially chiral quaternary amino acids, are still challenges. Considering asymmetric a-amination of branched aldehydes, easily and cheaply available, may be one of the most efficient and direct means to fulfill this goal and for further and deep understanding and expanding this useful asymmetric transformation, it is still desirable to develop simple, easily available catalysts for various multifunctional preparations of optically active chiral a,a-disubstituted amino compounds.…”

Asymmetric Synthesis of Quaternary α‐Amino Acids and Their Phosphonate Analogues

“…The Wang group later reported that a naphthyl-containing amino acid (C53) was a better catalyst for this amination reaction (Scheme 61). [76] Notably, C53 (20 mol %) promoted the reaction efficiently to provide the desired adducts 189 in high yields and stereoselectivities in most cases. In 2009, Maruoka and co-workers reported asymmetric a-amination of various b-ketoesters (190) with azodicarboxylate 188 in the presence of axially chiral phosphonium bromide C54 as a chiral catalyst and KH 2 PO 4 as a base (Scheme 62).…”

C2-symmetric BINOL-squaramide as efficient organocatalyst for the enantioselective α-amination of 1,3-dicarbonyl compounds with dialkyl azodicarboxylates

“…In 2010, Rawal et al developed the chiral squaramide organocatlyst derived from cyclohexane-1,2-diamine, which shown excellent catalytic performance in asymmetric a-hydrazination of 1,3-dicarbonyl compounds with azodicarboxylates [15]. More recently, Wang reported the amine-thiourea organocatalyst catalyzed the asymmetric amination of cyclic b-keto esters reaction [16]. Despite the progress has been made in recent years, the enantioselctive a-amination reaction catalyzed by BINOL-squaramides has been rarely described.…”