Reductive cross-coupling of aryl halides with ubiquitous alkyl tosylates was developed using a combination of nickel and vitamin B12 catalysts. The tosylate was activated by reduced vitamin B12 to form alkyl cobalt(III) which served as a good alkylating agent for aryl-nickel species, leading to the C(sp3)–C(sp2) bond formation.
A unique C–H allylation has been discovered with unbiased aliphatic olefins. An intimate M–L affiliation between a high-valent cobalt catalyst and amino-quinoline derived benzamides has been found to be crucial for this unprecedented selectivity. An exemplary set of aliphatic olefins, high yields coupled with excellent regio- and stereoselectivity, and wide functional group tolerances are noteworthy
Herein, we report the nor-AZADO-catalyzed exhaustive aerobic oxidations of 1,2-diols to α-keto acids. Combining oxidation with transamination using dl-2-phenylglycine led to the synthesis of free α-amino acids (AAs) in one pot. This method enables the rapid and flexible preparation of a variety of valuable unnatural AAs, such as fluorescent AAs, photoactivatable AAs, and other functional AAs for bioorthogonal
Synthesis of sphingosine relatives. Part 22. Synthesis of sulfobacin A, B and flavocristamide A, new sulfonolipids isolated from Chryseobacterium sp.
作者:Hirosato Takikawa、Dai Nozawa、Akihiro Kayo、Shin-etsu Muto、Kenji Mori
DOI:10.1039/a904258j
日期:——
Sulfobacin A (1), B (2), and flavocristamide A (3), new sulfonolipids isolated from Chryseobacterium sp. were synthesized stereoselectively by starting from L-cysteine.
Branch-Selective Addition of Unactivated Olefins into Imines and Aldehydes
作者:Jeishla L. M. Matos、Suhelen Vásquez-Céspedes、Jieyu Gu、Takuya Oguma、Ryan A. Shenvi
DOI:10.1021/jacs.8b11699
日期:2018.12.12
Herein we report the reductive coupling of electronically unbiased olefins with imines and aldehydes. Iron catalysis allows addition of alkyl-substituted olefins into imines through the intermediacy of free radicals, whereas a combination of catalytic Co(Sal t-Bu, t-Bu) and chromium salts enables a branch-selective coupling of olefins and aldehydes through the formation of a putative alkyl chromium intermediate