Synthesis of novel α-amino-acids and derivatives using radical chemistry: synthesis of - and -α-amino-adipic acids, -α

Decarboxylative couplings as versatile tools for late‐stage peptide modifications

“…This alkyl radical can engage in a number of downstream pathways including reduction to the corresponding alkane 8 in the presence of a hydrogen atom donor, such as tBuSH, or halogenation with CCl 4 or BrCCl 3 to afford the Hunsdiecker‐Borodin product 9 . Giese‐type radical addition to an electron deficient olefin followed by incorporation of a pyridylsulfide unit at the α‐position to the electron‐withdrawing group affords amino acid derivatives such as 10 (Scheme A) …”

“…Okada and coworkers demonstrated that radical intermediate 18 can subsequently engage a variety of radical traps, including tBuSH, CCl 4 , and various electron‐deficient olefins to afford the corresponding reduced alkanes 19 , chloroalkanes 20 , and Michael adducts 21 , respectively (Scheme C). The ability to forge addition products such as 21 is a notable advantage over the use of Barton esters, whereby the intermediate radical formed following Michael addition reacts preferentially with the Barton ester thiocarbonyl group to form α‐sulfide products such as 10 (see Scheme A) . In their 2012 second‐generation synthesis of the diterpene (–)‐aplyviolene, Schnermann and Overmann masterfully employed an NHPI ester to facilitate the decarboxylative addition of a tertiary radical to an α,β‐unsaturated ketone .…”

“…Drawing from the early successes of Barton and Okada on decarboxylative Giese reactions, Baran and coworkers extended their suite of on‐resin, nickel‐catalyzed RAE modifications to include reactions with electron‐deficient alkenes (Scheme A) . Following activation as the corresponding NHPI‐ester, resin‐bound acid 39 could be coupled with phenylvinylsulfone or acrylonitrile in the presence of Ni(acac) 2 , LiCl, and Zn powder to afford modified peptides 40 and 41 , respectively.…”

Microbial resolution of Nɛ-acetyl-dl-lysine with Rhodococcus sp. AIU Z-35-1

“…L--Aminoadipate -semialdehyde (L--AASA) and L--aminoadipic acid (L--AAA) are important precursors in biosynthesis of -lactam antibiotics or L-lysine (1,2). Since those precursors and their related compounds have become interesting raw materials for chemical synthesis of new antibiotics or physiologically active peptides, some chemical and biochemical methods for production of L--AASA, L--AAA or their derivatives have been developed (3)(4)(5)(6)(7)(8)(9). However, those methods were complicated and their conversion yields were low.…”

Does the Exception Prove the Rule? A Comparative Study of Supramolecular Synthons in a Series of Lactam Esters

“…1 H NMR: (500 MHz, MeOH-d4) δ 4.06 (dd, Jd = 4.8 Hz, Jdd = 8.9 Hz, 1H, H2); 2.30 (t, 3 J = 7.4 Hz, 2H, H6); 1.82-1.79 (m, 1H, H3); 1.65-1.62 (m, 3H; H5, H3'); 1.44-1.43 (m, 11H, H4, H10 HR-MS: calculated 276.1442 g/mol [M+H] +, found 276.1424 g/mol. Some analytical data of the respective L-enantiomer of 13 has already been described in the literature 56.…”