Asymmetric Synthesis of Substituted Prolines from δ-Amino β-Ketoesters. Methyl (2S,5R)-(+)-5-Phenylpyrrolidine-2-carboxylate

Abstract

[reaction: see text]. Metal carbenoid chemistry is used to convert delta-amino beta-ketoesters into 5-substituted 3-oxo prolines, which expands the utility of this class of polyfunctionalized chiral building blocks.

Enantiodivergent Synthesis of (+)‐ and (−)‐Pyrrolidine 197B: Synthesis of trans‐2,5‐Disubstituted Pyrrolidines by Intramolecular Hydroamination

“…On the other hand, the synthesis of proline derivatives such as 8 having an additional ester in ad istal position allows further modifications as well. Furthermore, our methodc omplements the known syntheses of 5-substitutedp rolines based, amongo thers, on Strecker-type reaction, [28] reductive amination, [29] 5-endo-dig cyclization, [30] addition of Grignard reagents to oxazolidines, [31] b-decarboxylation/N-cyclization, [32] carbenoid chemistry, [33] hydroboration/oxidationr eaction, [34] oxidative cleavage of bicyclic skeletons, [35] and radical cyclization. [36] The scope of our methodology was checked next.…”

Diastereoselective addition of lithium enolate of γ-substituted α-diazoacetoacetate to N-sulfinyl imines

“…For chromatography, 200-300 mesh silica gel (Qindao, China) was employed. 1 H and 13 C NMR spectra were recorded at 300 and 75 MHz with Varian Mercury 300 spectrometer. Chemical shifts are reported in ppm using tetramethylsilane as internal standard.…”

“…As a consequence, numerous methodologies have been developed for their synthesis over the years [4][5][6][7][8][9][10][11][12][13][14]. Among various methods, the application of chiral sulfinimines is practical and reliable [13].…”

“…As a consequence, numerous methodologies have been developed for their synthesis over the years [4][5][6][7][8][9][10][11][12][13][14]. Among various methods, the application of chiral sulfinimines is practical and reliable [13]. Davis's N-ptolylsulfinimines [15][16][17][18][19][20][21][22][23][24][25][26] and Ellman's N-tert-butyl derivatives [27][28][29][30] are the two representatives which have been successfully utilized in a variety of transformations.…”

Rhodium(II)-Catalyzed Reaction of Diazocompounds in the Service of Organic Synthesis of Natural and Non-Natural Products

“…N-Boc δ-amino αdiazoketo ester 154 underwent efficient N-H insertion [36] when exposed to catalytic amounts of Rh 2 (OAc) 4 (Scheme 32). The optimal reaction temperature was found to be - 3-Oxoprolines are useful chiral, non-racemic building blocks for the preparation of non-natural α-amino acids, which are used in peptide synthesis.…”