400724-48-3Relevant articles and documents
Synthesis of 2,2-disubstituted pyrrolidine-4-carboxylic acid derivatives and their incorporation into β-peptide oligomers
Huck, Bayard R.,Gellman, Samuel H.
, p. 3353 - 3362 (2007/10/03)
(Chemical Equation Presented) We have recently shown that members of a new class of β-peptides, containing 2,2-disubstituted pyrrolidine-4-carboxylic acid residues, display discrete conformational preferences despite the impossibility of internal hydrogen bonding (Huck et al. J. Am. Chem. Soc. 2003, 125, 9035). Here we describe the synthesis of a variety of 2,2-disubstituted pyrrolidine-4-carboxylic derivatives that bear a diverse set of side chains and protecting groups suitable for oligomer synthesis. In addition, we discuss coupling methods for construction of oligomers in solution and on solid phase. Non-hydrogen bonded foldamers such as those generated from 2,2-disubstituted pyrrolidine-4-carboxylic acids may be useful in biomedical applications because the low intrinsic polarity of their backbones may promote bioavailability.
Diastereoselective synthesis of 2-alkylated 4-silyloxyproline esters
Sato,Kawasaki,Oda,Yagi,El Bialy,Uenishi,Yamauchi,Ikeda
, p. 2623 - 2631 (2007/10/03)
Treatment of the 4-silyloxy-N-Boc-L-proline methyl ester 1 with allyl bromide in the presence of LDA in THF at -78°C gives a mixture of the (2S,4R)- and (2R,4R)-2-(prop-2-enyl)-4-silyloxy-N-Boc-L-proline esters 2a and 2b in 75% combined yield in the ratio 53:47. In contrast, similar treatment of the (-)- and (+)-menthyl esters 5 and 6 gives a mixture of allylated products 7a,b and 8a,b in the ratio 75:25 and 89:11, respectively. Reaction of 6 with methyl iodide and propyl iodide also give the corresponding 2-alkylated esters 16a and 16b in a highly diastereoselective manner (94:6 and 93:7, respectively).