Solventless and metal-free regioselective hydrofluorination of functionalized alkynes and allenes: an efficient protocol for the synthesis of <i>gem</i>-difluorides
作者:Zhichao Lu、Bhvandip S. Bajwa、Shiwen Liu、Sheye Lee、Gerald B. Hammond、Bo Xu
DOI:10.1039/c8gc03876g
日期:——
The combination of two easily handled, highly acidic liquid HF complex reagents, DMPU-12HF and KHSO4-13HF, generated a highly acidic fluorination system that facilitated exclusive Markovnikov addition of HF to widely functionalized alkynes, including alkyne tethered drugs, or allenes to produce gem-difluorides with high atom economy, and with an easy workup.
Rhodium(III)-Catalyzed [4+1] Annulation of Aromatic and Vinylic Carboxylic Acids with Allenes: An Efficient Method Towards Vinyl-Substituted Phthalides and 2-Furanones
A highly regio‐ and stereoselective synthesis of 3,3‐disubstituted phthalides from aryl carboxylic acids and allenes using a rhodium(III) catalyst has been demonstrated. The reaction features broad functional group tolerance and provides a simple and straightforward route to the synthesis of various 3‐vinyl‐substituted phthalides. Furthermore, the catalytic reaction can also be applied to the synthesis
Rhodium-Catalyzed Enantioselective Decarboxylative Alkynylation of Allenes with Arylpropiolic Acids
作者:Christian P. Grugel、Bernhard Breit
DOI:10.1021/acs.orglett.7b04035
日期:2018.2.16
A rhodium-catalyzed chemo-, regio-, and enantioselective intermolecular decarboxylative alkynylation of terminal allenes with arylpropiolic acids is reported. Employing a Rh(I)/(R)-Tol-BINAP catalytic system, branched allylic 1,4-enynes were obtained under mild conditions. The overall utility of this protocol is exemplified by a broad functional group compatibility.
Rhodium-Catalyzed Cross-Cyclotrimerization and Dimerization of Allenes with Alkynes
作者:Kazuki Sakashita、Yu Shibata、Ken Tanaka
DOI:10.1002/anie.201602155
日期:2016.6.1
It has been established that a cationicrhodium(I)/binapcomplex catalyzes the cross‐cyclotrimerization of two molecules of a monosubstituted allene with one molecule of a functionalized alkyne to give 3,6‐dialkylidenecyclohex‐1‐enes. In contrast, the reactions involving di‐ or trisubstituted allenes and/or unfunctionalized alkynes afforded cross‐dimerization products, substituted dendralenes, through
The catalyticCHaddition of pyridines to allenes has been achieved for the first time by using a half‐sandwich scandium catalyst, thus constituting a straightforward and atom‐economical route for the synthesis of alkenylated pyridine derivatives. The reaction proceeded regio‐ and stereoselectively, affording a new family of alkenylated pyridine compounds which are otherwise difficult to synthesize