Mechanism of the Iron(II)-Catalyzed Hydrosilylation of Ketones: Activation of Iron Carboxylate Precatalysts and Reaction Pathways of the Active Catalyst
作者:Tim Bleith、Lutz H. Gade
DOI:10.1021/jacs.6b02173
日期:2016.4.13
isolation of the catalytically active alkoxide intermediate, and DFT-modeling of the whole reaction sequence. The proposed reaction mechanism is characterized by a rate-determining σ-bond metathesis of an alkoxide complex with the silane, subsequent coordination of the ketone to the iron hydride complex, and insertion of the ketone into the Fe-H bond to regenerate the alkoxide complex.
Allylic C−H Acetoxylation with a 4,5-Diazafluorenone-Ligated Palladium Catalyst: A Ligand-Based Strategy To Achieve Aerobic Catalytic Turnover
作者:Alison N. Campbell、Paul B. White、Ilia A. Guzei、Shannon S. Stahl
DOI:10.1021/ja105829t
日期:2010.11.3
Pd-catalyzed C-H oxidation reactions often require the use of oxidants other than O(2). Here we demonstrate a ligand-based strategy to replace benzoquinone with O(2) as the stoichiometric oxidant in Pd-catalyzed allylic C-H acetoxylation. Use of 4,5-diazafluorenone (1) as an ancillary ligand for Pd(OAc)(2) enables terminal alkenes to be converted to linear allylic acetoxylation products in good yields
Substrate geometry controls the cyclization cascade in multiproduct terpene synthases from Zea mays
作者:Abith Vattekkatte、Nathalie Gatto、Tobias G. Köllner、Jörg Degenhardt、Jonathan Gershenzon、Wilhelm Boland
DOI:10.1039/c5ob00711a
日期:——
Multiproduct terpene synthases on incubation with (2Z) substrates showed enhanced enzymatic turnover with distinct preference for cyclic products than corresponding (2E) substrates.
A convenient synthesis of isotopically labelled anthraquinones, chrysophanol, islandicin, and emodin. Incorporation of [methyl-2H3]chrysophanol into tajixanthone in Aspergillus variecolor
作者:Salman A. Ahmed、Esfandiar Bardshiri、Thomas J. Simpson
DOI:10.1039/c39870000883
日期:——
Cycloaddition reactions of labelled 6-methoxy-3-methyl-2-pyrone (1) with naphthoquinones provide the common fungal anthraquinones, chrysophanol (2), islandicin (3), and emodin (4) suitably labelled for biosynthetic studies, as demonstrated by synthesis and incorporation of [methyl-2H3]chrysophanol into the xanthone metabolite, tajixanthone (17) in Aspergillusvariecolor.