ChemInform Abstract: 1,2‐Amino Alcohols and Their Heterocyclic Derivatives as Chiral Auxiliaries in Asymmetric Synthesis

Abstract

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Synthesis of Unnatural/Nonproteinogenic α‐Amino Acids

“…In this example, quinine was used as the resolving agent [8,9]. 12 [10,11] and Evans [12][13][14] auxiliary methods, and there are many examples in the literature that there is a high probability of success with an analogous system [13]. The methodology is excellent for smaller-scale applications.…”

“…Phenylglycinol (14) itself can be used as a chiral template transferring the nitrogen in an asymmetric Strecker reaction (Scheme 12.16). However, in some examples of this approach, caution must be exercised as epimerization has been observed during hydrolysis of the nitrile group [60][61][62][63].…”

“…N-Acyl-oxazolidinones are readily available and the use of this class of compounds for the preparation of unnatural amino acids has been well documented [13,14]. Di-tert-butyl azodicarboxylate reacts readily with the lithium enolates of N-acyloxazolidinones to provide hydrazides 11 in excellent yield and high diastereomeric ratio (Scheme 12.13) (see Section 12.5.2) [49,50].…”

Electrogenerated N-heterocyclic carbene: N-acylation of chiral oxazolidin-2-ones in ionic liquids

“…The set up of a methodology for chiral auxiliary mediated asymmetric carbon-carbon bond formation may be an interesting goal in organic synthesis [1][2][3]. Chiral oxazolidin-2-ones have been frequently utilized as chiral auxiliaries (Evans' chiral auxiliaries) [4,5] in asymmetric synthesis.…”

Synthesis and stereoselective oxidation of α-thio-β-chloropropenyloxazolidin-2-ones

“…[5][6][7][8][9][10] Chiral 2-oxazolidinones, first reported by Evans in 1981, 5 have proven to be highly versatile chiral auxiliaries, with high asymmetric induction achieved in alkylations, aminations, azidations, brominations, hydroxylations, aldol additions, DielsAlder cycloadditions and conjugate reactions. [6][7][8][9] Therefore, we wished to extend this chlorination chemistry to α-thiopropanoyloxazolidin-2-ones, and explore the asymmetric induction in reactions of the resulting α-thio-β-chloropropenyloxazolidin-2-ones, focussing specifically on diastereoselective oxidation (Scheme 1). We have recently shown that with simple chiral amide auxiliaries, some, albeit modest, diastereocontrol is possible.…”