Stereoselectivity of Additions to N-Methyl Acetonitrilium Fluorosulfonate
摘要:
Alkoxy-N-methyl-acetiminium salts were prepared by addition of CH3OH and C2H5OH to N-methyl acetonitrilium fluorosulfonate at low temperature. Analysis of the (5)J(HH) and (3)J(13)C-H coupling constants in the NMR spectra showed an anti addition with a diastereoselectivity of >9596. Deprotonation of these salts with (Z)-configuration gave the corresponding N-methyl-alkoxyacetimines with very high (E)-configuration. Upon protonation at -78 degrees C, these iminoesters gave the corresponding alkoxy-N-methyl-acetirninium salts with (E)-configuration. Computational analyses of the iminoesters and the corresponding iminium cations including the conformations give insight into the relative stability. Nitrilium salts can be used as reagents, exemplified by some esterifications between simple acids and alcohols.
A general and environmentally improved protocol for the cyanation of aryl halides with the nontoxic cyanidesourcepotassiumhexacyanoferrate(II) (K 4 [Fe(CN) 6 ]) using copper catalysis and a ligand system based on l-alkyl-1H -imidazoles is presented. The advantages of this system are a wide substrate range, high selectivity, easy handling, and inexpensive reagents.
使用铜催化和基于 l-烷基-1H-咪唑的配体系统,用无毒氰化物源六氰基铁酸钾 (II) (K 4 [Fe(CN) 6 ]) 氰化芳基卤化物的通用和环境改进方案是呈现。该系统的优点是底物范围广、选择性高、易于处理和试剂便宜。
A State-of-the-Art Cyanation of Aryl Bromides: A Novel and Versatile Copper Catalyst System Inspired by Nature
A general protocol for the cyanation of aryl halides with the nontoxic cyanide source K4[Fe(CN)6] using copper catalysis and a ligand system based on 1-alkylimidazoles is presented. The advantages of this system are the high selectivity, a unique substrate range, easy handling, and inexpensive reagents.
Transnitrilation from Dimethylmalononitrile to Aryl Grignard and Lithium Reagents: A Practical Method for Aryl Nitrile Synthesis
作者:Jonathan T. Reeves、Christian A. Malapit、Frederic G. Buono、Kanwar P. Sidhu、Maurice A. Marsini、C. Avery Sader、Keith R. Fandrick、Carl A. Busacca、Chris H. Senanayake
DOI:10.1021/jacs.5b06136
日期:2015.7.29
An electrophilic cyanation of aryl Grignard or lithium reagents, generated in situ from the corresponding aryl bromides or iodides, by a transnitrilation with dimethylmalononitrile (DMMN) was developed. DMMN is a commercially available, bench-stable solid. The transnitrilation with DMMN avoids the use of toxic reagents and transition metals and occurs under mild reaction conditions, even for extremely
Electrochemical Benzylic C–H Functionalization with Isocyanides
作者:Shanyu Tang、Régis Guillot、Laurence Grimaud、Maxime R. Vitale、Guillaume Vincent
DOI:10.1021/acs.orglett.2c00364
日期:2022.3.25
We report the challenging direct carbamoylation or cyanation of benzylic C(sp3)–H bonds with an isocyanide via an electrochemical process giving rise to structures that are encountered in several biologically relevant compounds and drugs. This transformation proceeds under mild conditions without the need for any external oxidant and avoids the necessity to start from a prefunctionalized benzylic substrate