38018-61-0Relevant articles and documents
Ni-Catalyzed asymmetric reduction of α-keto-β-lactams: via DKR enabled by proton shuttling
Wang, Fangyuan,Tan, Xuefeng,Wu, Ting,Zheng, Long-Sheng,Chen, Gen-Qiang,Zhang, Xumu
supporting information, p. 15557 - 15560 (2020/12/30)
Chiral α-hydroxy-β-lactams are key fragments of many bioactive compounds and antibiotics, and the development of efficient synthetic methods for these compounds is of great value. The highly enantioselective dynamic kinetic resolution (DKR) of α-keto-β-lactams was realized via a novel proton shuttling strategy. A wide range of α-keto-β-lactams were reduced efficiently and enantioselectively by Ni-catalyzed asymmetric hydrogenation, providing the corresponding α-hydroxy-β-lactam derivatives with high yields and enantioselectivities (up to 92% yield, up to 94% ee). Deuterium-labelling experiments indicate that phenylphosphinic acid plays a pivotal role in the DKR of α-keto-β-lactams by promoting the enolization process. The synthetic potential of this protocol was demonstrated by its application in the synthesis of a key intermediate of Taxol and (+)-epi-Cytoxazone. This journal is
Organocatalytic Mukaiyama Mannich Reactions of 2,5-Bis(trimethylsilyloxy)furan
Laws, Stephen W.,Howard, Sara Y.,Mato, Raquel,Meng, Shuyu,Fettinger, James C.,Shaw, Jared T.
supporting information, p. 5073 - 5077 (2019/07/03)
The organocatalytic synthesis of densely substituted mono- and bis-?-lactams involving the Mukaiyama Mannich addition of 2,5-bis(trimethylsilyloxy)furan to imines is described. Use of a ditoluenesulfonylimide catalyst produces ?-lactams from monoaddition, whereas a more acidic catalyst (triflic acid) produces fused bis-lactams from double addition. Optimized organocatalytic conditions allow for the selective synthesis of either desired core as well as the one-pot, multicomponent assembly of the trisubstituted monolactams from aldehydes, amines, and bis-trimethylsilyloxyfuran. An examination of chiral acids found these organocatalysts to be highly active and diastereoselective in the monoaddition reaction, albeit with no enantioselectivity.
Paclitaxel Biosynthesis: Adenylation and Thiolation Domains of an NRPS TycA PheAT Module Produce Various Arylisoserine CoA Thioesters
Muchiri, Ruth,Walker, Kevin D.
, p. 1415 - 1425 (2017/03/23)
Structure-activity relationship studies show that the phenylisoserinyl moiety of paclitaxel (Taxol) is largely necessary for the effective anticancer activity. Several paclitaxel analogues with a variant isoserinyl side chain have improved pharmaceutical
