TY  - JOUR
A1  - Pape, Simon
A1  - Wessig, Pablo
A1  - Brunner, Heiko
T1  - Iron Trichloride and Air Mediated Guanylation of Acylthioureas. An Ecological Route to Acylguanidines: Scope and Mechanistic Insights
JF  - The journal of organic chemistry
N2  - Recently we introduced iron trichloride as an environmentally benign and cost-efficient reagent for the synthesis of N-benzoylguanidines. This highly attractive synthetic approach grants access to a broad spectrum of N-benzoylguanidines under mild conditions in short reaction times. In this work we present an extended scope of Our methodology along with the results obtained from mechanistic studies via in situ IR spectroscopy in combination with LC (liquid chromatography)-MS analyses. On the basis of these new mechanistic insights we were able to optimize the synthetic protocol and to develop an alternative mechanistic proposal. In this context the symbiotic roles of iron trithloride and oxygen in the guanylation process are highlighted.
Y1  - 2016
U6  - https://doi.org/10.1021/acs.joc.6b00600
SN  - 0022-3263
VL  - 81
SP  - 4701
EP  - 4712
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Schmidt, Bernd
A1  - Wolf, Felix
A1  - Brunner, Heiko
T1  - Styrylsulfonates and -Sulfonamides through Pd-Catalysed Matsuda-Heck Reactions of Vinylsulfonic Acid Derivatives and Arenediazonium Salts
JF  - European journal of organic chemistry
N2  - Arene diazonium salts undergo Matsuda-Heck reactions with vinylsulfonates and -sulfonamides to give styrylsulfonic acid derivatives in high to excellent yields and with high to excellent selectivities. By quantifying the evolution of nitrogen over time in a gas-meter apparatus, the reactivities of ethylvinylsulfonate and the benchmark olefin methyl acrylate were compared for an electron-rich and an -deficient arene diazonium salt. Tertiary sulfonamides react in Matsuda-Heck couplings with high conversions, but require long reaction times, which prevents the determination of kinetic data through the measurement of nitrogen evolution. Secondary sulfonamides were found to be unreactive. From these results, the following order of reactivity could be deduced: H2C=CHCO2Me > H2C=CHSO2OEt > H2C=CHSO2N(Me)Bn >> H2C=CHSO2NHBn. Through the Matsuda-Heck coupling of 5-indolyldiazonium salt and a tertiary vinylsulfonamide, the synthesis of the C-5-substituted indole part of the antimigraine drug naratriptan was accomplished in high yield.
KW  - Homogeneous catalysis
KW  - Cross-coupling
KW  - Palladium
KW  - Sulfonamides
KW  - Alkenes
KW  - Drug design
Y1  - 2016
U6  - https://doi.org/10.1002/ejoc.201600469
SN  - 1434-193X
SN  - 1099-0690
SP  - 2972
EP  - 2982
PB  - Wiley-VCH
CY  - Weinheim
ER  -