Asymmetric Isothiourea-Catalysed Formal [3+2] Cycloadditions of Ammonium Enolates with Oxaziridines
作者:Siobhan R. Smith、Charlene Fallan、James E. Taylor、Ross McLennan、David S. B. Daniels、Louis C. Morrill、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1002/chem.201501271
日期:2015.7.13
A highly enantioselective Lewis base‐catalysed formal [3+2] cycloaddition of ammonium enolates and oxaziridines to give stereodefined oxazolidin‐4‐ones in high yield is described. Employing an enantioenriched oxaziridine in this process leads to a matched/mis‐matched effect with the isothiourea catalyst and allowed the synthesis of either syn‐ or anti‐stereodefined oxazolidin‐4‐ones in high d.r., yield
Silver‐catalyzed oxidative decarboxylative couplings of carboxylic acids and anhydrides to produce 1,2‐diketones and substituted ethanes were developed. This reaction allows the generation of acyl or alkyl radicals by decarboxylation of the corresponding α‐keto acids, alkyl acids and anhydrides, which are sequentially coupled to efficiently construct a new C−C bond. This reaction represents a carboxylic
Light/Palladium‐Promoted Benzylic C−H Acylation Using a Benzoyl Group as the Photo‐Directing Group
作者:Yusuke Masuda、Naoki Ishida、Masahiro Murakami
DOI:10.1002/asia.201801881
日期:2019.2
2‐Methylphenyl ketones undergo site‐selective acylation at the benzylic position when treated with acid anhydride under UV irradiation in the presence of a palladium catalyst. The benzoyl carbonyl group serves as the photo‐directinggroup so that the ortho benzylicC−H bond is activated site‐selectively.
The photochemistry of α-aryl carboxylic anhydrides—II
作者:A.A.M. Roof、H.F. van Woerden、H. Cerfontain
DOI:10.1016/0040-4020(76)80154-8
日期:——
phenylacetic acids and anhydrides with λ 254 nm was studied. The main product is bibenzyl, but with o- and p-methoxyphenylacetic anhydride, in addition substantial amounts of methoxybenzyl methoxyphenylacetates are formed. The photoreactivity of phenylacetic acid strongly reduces upon substitution of the phenyl ring, this in contrast to the behaviour of the corresponding anhydrides. The quantum yields