Efficient synthesis of 3-hydroxyprolines and 3-hydroxyprolinols from sugars

Synthesis of All Four Stereoisomers of 3-Amino-2-hydroxybutanoic Acids

“…Treatment of iodide 12 with n-BuLi at À40 C generated (3R,4R) aminoalcohol 13 {½ 20 D À287:6 (c 4.00, CHCl 3 )} in an 89% yield through simultaneous dealkoxyhalogenation. 12,15) The secondary hydroxyl group of 13 was easily protected with BnBr to give benzylate 14 in a 91% yield. Ozonolysis of benzylate 14 and subsequent H 2 O 2 oxidation afforded protected (2S,3R)-3-amino-2-hydroxybutanoic acid 15.…”

“…NH 4 Cl (30 ml), before the mixture was extracted with EtOAc (90 ml). After concentrating the combined extracts, the residue was purified by silica gel column chromatography (EtOAchexane, 1:8) to give benzylate 14 (1.15 g, 91%) as an oil, ½ (15). A solution of benzylate 14 (0.80 g, 1.85 mmol) in CH 3 OH (16 ml) was ozonized at À78 C until the solution turned blue, the residual ozone then being removed by purging with N 2 gas.…”

Methods for the Chemical Synthesis of Noncoded α‐Amino Acids found in Natural Product Peptides

“…In particular, castanospermines, slaframine, and detoxinine are known as potent glycosidase inhibitors [28,29], where their analogs serve as lead compounds in the development of novel antiviral agents. Due to the prevalence of 3-OH Pro in various bioactive natural products, many useful asymmetric synthetic methods have been reported to prepare both diastereomers of 3-OH Pro [30][31][32][33][34][35][36][37][38][39].…”

“…Careful manipulations of the functional groups on the sugar molecule can eliminate the use of chiral catalysts or chiral auxiliaries, which can be expensive and can add more synthetic steps, although sometimes trivial, to completion of a target molecule. As an example, Park et al have used relatively inexpensive sugar molecules, D-glucono-d-lactone and L-gluconic acid g-lactone, to prepare two diastereomers of 3-OH Pro [35].…”

Chirospecific Synthesis of D-erythro- and L-threo-Sphinganines from Sugars

“…For example, we reported the synthetic route of 2-amino-3-hydroxy-4-pentenoic acid derivatives via a simultaneous dealkoxyhalogenation. 7 Here, we describe the synthesis of D-erythro-sphinganine 1 and L-threo-sphinganine 2 by homochiral synthetic techniques from L-glucono-1,5-lactone and L-gulonic acid γ-lactone. Our general retrosynthesis of target molecules 1 and 2 is outlined in Figure 1.…”