An efficient asymmetric synthesis of the mercaptopyrrolidine side chain of an important β-methyl carbapenem antibiotic

The structure and biosynthesis of heinamides A1–A3 and B1–B5, antifungal members of the laxaphycin lipopeptide family

“…Hydroxyprolines are important in the pharmaceutical industry and are produced through enzymatic reactions. [46][47][48][49] (2S,4R)-4-OHPro is used in the production of carbapenem antibiotics 50,51 and the anti-inflammatory agent oxaceprol. 52 In human physiology, (2S,4R)-4-OHPro has a role in increasing collagen stability and has been shown to facilitate collagen biosynthesis in rats 53 and is used in skin care products as Pro-(2S,4R)-4-OHPro dipeptides.…”

Mitsunobu and Related Reactions: Advances and Applications

“…1399 These compounds are potential substrates for the monolayer protection of 2D surfaces and nanoparticles. Related chemistry using thioacids has been made use of in the synthesis of (i) 2,5-anhydro-3-azido-2-thio-D-lyxofuranosides and 3,5-anhydro-2-azido-3-thio-D-lyxofuranosides, 1400 (ii) highly oxygenated triterpene quassinoids, 1401 (iii) anhydro-thiohexofuranosides, 1402 (iv) dihydrothiophene derivatives, 1403 (v) (2S,3E)-5-(isopropylsulfanyl)-3-pentenes, 1404 (vi) thio-disaccharides, 1405 (vii) mercaptopyrrolidines, 1406 (viii) 2-oxa-7thiabicyclo[4.2.0]octane derivatives with the D-galacto and D-gulo configurations, 1407 (ix) functionalized long-chain etherlinked thiols for use in developing monolayers of gold, 1408 (x) (R)-4,4,4-trifuoro-2-mercaptobutyric acid starting from (S)-malic acid, 1409 (xi) diastereoisomeric 3-methoxy-2-oxa-6-thiabicyclo[3.2.0]heptan-4-ols, 1410 (xii) R-acetylsulfanylphosphonates, 1411 (xiii) S-adenosyl-L-homocysteine analogues, 1412 (xiv) 3-mercaptoproline derivatives, 1413 (xv) L-methionine/L-homocysteine from the protected homoserine, 1414 (xvi) allenic monocarboxylates, 1415 (xvii) C 5 thioalkynyl nucleosides, 1416 (xviii) azole nucleoside 5′monophosphate mimics (PIMs), 1417 and (xix) anhydrothiohexofuranosides. 1418 Another route to thiol from a primary alcohol involved the use of zinc dimethyldithiacarbamate (Ziram) in the Mitsunobu protocol.…”

Diastereoselective Hydrogenation

“…The hydrogenation of a b-keto ester with a carbamate unit at the c-position ((S)-substrate) in the presence of Ru-(R)-binap (matched pair) exclusively afforded the threo product with the (3S,4S) configuration, whereas in the presence of Ru-(S)-binap (mismatched pair) the (3R,4S)-product was formed preferentially (Table 21.15, entry 1) [96]. The b-keto esters with a pyrrolidine unit showed similar behavior (entry 4) [97]. A silyloxy group at the d-position could dictate the sense of asymmetric induction, and high diastereoselectivity is induced by using an achiral ruthenium catalyst, whereas the chiral ruthenium (R)-binap catalyst and the (S)-binap catalyst (matched and mismatched pairs, respectively) afford the same diastereomer, albeit in different selectivity (entry 7).…”