Regiocontrol and Stereoselectivity in Tungsten-Bipyridine Catalysed Allylic Alkylation
摘要:
Tungsten-bipyridine complexes, generated in situ, catalyse the allylic alkylation of isocinnamyl methyl carbonate by dimethyl sodiomalonate [NaCH(CO2CH3)(2)] with complete syn-stereoselectivity. When para substituted aryl-allyl methyl carbonates are employed, the regioselectivity correlates with Swain-Lupton parameters. Cross-over experiments demonstrate that the reactions do not procede via the conventional [M(0)] --> [M(II) allyl](+) --> [M(0) allyl-Nu] catalytic cycle.
Recoverable Resin-Supported Pyridylamide Ligand for Microwave-Accelerated Molybdenum-Catalyzed Asymmetric Allylic Alkylations: Enantioselective Synthesis of Baclofen
作者:Oscar Belda、Stina Lundgren、Christina Moberg
DOI:10.1021/ol034605m
日期:2003.6.1
microwave-accelerated molybdenum-catalyzedasymmetricallylicalkylation. The reaction afforded the product in high yield and with high regio- and enantioselectivity. The heterogeneous ligand could be reused several times with no change in the reaction outcome. The asymmetricallylicalkylation was employed as the key step in the enantioselective synthesis of (R)-baclofen. [reaction: see text]
Chemo-, Regio- and Stereoselective Heck Arylation of Allylated Malonates: Mechanistic Insights by ESI-MS and Synthetic Application toward 5-Arylmethyl-γ-lactones
作者:Caio C. Oliveira、Marcelo V. Marques、Marla N. Godoi、Thaís Regiani、Vanessa G. Santos、Emerson A. F. dos Santos、Marcos N. Eberlin、Marcus M. Sá、Carlos R. D. Correia
DOI:10.1021/ol502529v
日期:2014.10.3
We describe herein a general method for the controlled Heck arylation of allylated malonates. Both electron-rich and electron-poor aryldiazonium salts were readily employed as the aryl-transfer agents in good yields and in high chemo-, regio-, and stereoselectivity without formation of decarboxylated byproducts. Reaction monitoring via ESI-MS was used to support the formation of chelated Pd species
An Ir-catalyzed asymmetric allylic alkylation using chiral diaminophosphine oxide is described. Asymmetric allylic alkylation of terminal allylic carbonates proceeded using 5 mol % of Ir catalyst, 5 mol % of DIAPHOX 1i, 10 mol % of NaPF6, 10 mol % of LiOAc, and N,O-bis(trimethylsilyl)acetamide (BSA), affording the corresponding branched products in excellent yield and in up to 95% ee. The developed
Ferrocenyliminophosphites as Easy-to-Modify Ligands for Asymmetric Catalysis
作者:Konstantin N. Gavrilov、Marina G. Maksimova、Sergey V. Zheglov、Oleg G. Bondarev、Eduard B. Benetsky、Sergey E. Lyubimov、Pavel V. Petrovskii、Anzhelika A. Kabro、Evamarie Hey-Hawkins、Sergey K. Moiseev、Valery N. Kalinin、Vadim A. Davankov
DOI:10.1002/ejoc.200700396
日期:2007.10
phosphite-type ligands derived from readily available ferrocene-based iminoalcohols were successfully used in Rh-catalysed hydrogenations and Pd-catalysed allylic substitutions of a variety of substrates. Moderate-to-high catalytic activities under standard conditions were observed, and the enantiomeric excess of the products were up to 97 %. Results obtained under systematic variation of the ligand parameters
Substituted Pyridylamide Ligands in Microwave-Accelerated Mo(0)-Catalysed Allylic Alkylations
作者:Christina Moberg、Oscar Belda
DOI:10.1055/s-2002-33345
日期:——
bis-pyridylamides were prepared by microwave accelerated nucleophilic substitution of the 4-and 6-halo substituted derivatives of the parent ligand la. The ligands were used in the asymmetric allylation of cinnamyl carbonate catalysed by Mo(0) in which the 4-chloro- and 4-pyrrolidyl substituted ligand derivatives exhibited high regioselectivity (74:1 and 88:1. respectively) and enantioselectivity (96% ee), whereas