Room ‐Temperature Arylation of Thiols: Breakthrough with Aryl Chlorides
: The formation of aryl C −S bonds is an important chemical transformation because aryl sulfides are valuable building blocks for the synthesis of biologically and pharmaceutically active molecules and organic... (Source: Organometallic Current)
Source: Organometallic Current - December 12, 2016 Category: Chemistry Tags: C-S Bond Forming Room Temp Rxn Source Type: blogs
Rapid heteroatom transfer to arylmetals utilizing multifunctional reagent scaffolds
Hongyin Gao, Zhe Zhou, Doo-Hyun Kwon, James Coombs, Steven Jones, Nicole Erin Behnke, Daniel H. Ess& L ászló KürtiNature Chemistry (2016) doi:10.1038/nchem.2672The direct transfer of primary amino and hydroxyl groups to arylmetals in a scalable and environmentally friendly fashion remains a formidable synthetic challenge. Here, it is demonstrated that bench-stable N –H andN–alkyl oxaziridines can be used as efficient multifunctional reagents, without deprotonation, for the direct primary amination and hydroxylation of (hetero)arylmetals. (Source: Organometallic Current)
Source: Organometallic Current - December 7, 2016 Category: Chemistry Tags: Grignard Reagents Heterocycles Source Type: blogs
Aldehydes as alkyl carbanion equivalents for additions to carbonyl compounds
Haining Wang, Xi-Jie Dai& Chao-Jun LiNature Chemistry (2016) doi:10.1038/nchem.2677Methods utilizing renewable feedstocks are critical to accessing molecules of industrial importance in light of the present ecological and economic climate. Here, it is shown thatumpolung reactivity of carbonyl compounds can be used for nucleophilic additions to yield a diverse array of valuable alcohols as an alternative to using stoichiometric organometallic reagents. (Source: Organometallic Current)
Source: Organometallic Current - December 7, 2016 Category: Chemistry Tags: Ru catalyzed Umpolung Source Type: blogs
Direct assembly of multiply oxygenated carbon chains by decarbonylative radical –radical coupling reactions
Kengo Masuda, Masanori Nagatomo& Masayuki InoueNature Chemistry 8, 1105 –1111 (2016)doi:10.1038/nchem.2636Pentoses and hexoses represent important structural motifs in bioactive secondary metabolites, though their synthesis often requires several elongation steps. Now, a method for radical –radical coupling reactions of sugar derivatives enables the single-step preparation of the oxygenated carbon chains of several natural products, including sagittamide D, maitotoxin and hikizimycin. (Source: Organometallic Current)
Source: Organometallic Current - December 7, 2016 Category: Chemistry Tags: Radical Reactions Source Type: blogs
Remote C −H alkylation and C−C bond cleavage enabled by an in situ generated palladacycle
Juntao Ye, Zhihao Shi, Theresa Sperger, Yoshifumi Yasukawa, Cian Kingston, Franziska Schoenebeck& Mark LautensNature Chemistry (2016) doi:10.1038/nchem.2631Existing methods for C –H activation depend on preinstalled directing groups, the removal of which poses a practical limitation on the use of these reactions in synthesis. Now, a remote-selective C−H alkylation reaction of arenes using anin situ generated spiropalladacycle has been shown to furnish benzofurans and indoles without the need for a directing group. (Source: Organometallic Current)
Source: Organometallic Current - December 7, 2016 Category: Chemistry Tags: C-C cleavage C-H alkylation Pd Catalyzed Source Type: blogs
Enantioselective amine α-functionalization via palladium-catalysed C–H arylation of thioamides
Pankaj Jain, Pritha Verma, Guoqin Xia& Jin-Quan YuNature Chemistry (2016) doi:10.1038/nchem.2619Chiral, saturated N-heterocycles are prized as pharmaceutical agents and chiral auxiliaries, but are challenging to access without using prefunctionalized starting materials. Now, chiral phosphoric acids are found to enable the enantioselective Pd(II)-catalysed arylation ofα-methylene C –H bonds in a wide variety of amines using thioamide as the directing group. (Source: Organometallic Current)
Source: Organometallic Current - December 7, 2016 Category: Chemistry Tags: C-H arylation Enantioselective Pd Catalyzed Source Type: blogs
F – Nucleophilic-Addition-Induced Allylic Alkylation - Journal of the American Chemical Society (ACS Publications)
Herein we present a novel strategy based on palladium-catalyzed allylic alkylation by taking advantage of the nucleophilic addition of external fluoride ontogem-difluoroalkenes as the initiation step. The merit of this protocol is highly appealing, as it enables a formal allylation of trifluoroethylarene derivatives through the in situ generation of β-trifluorocarbanions, which otherwise are deemed to be problematic in deprotonative allylation. (Source: Organometallic Current)
Source: Organometallic Current - December 6, 2016 Category: Chemistry Tags: Alkylation Allylic Fluorination Pd Catalyzed Source Type: blogs
Stereospecific Construction of Contiguous Quaternary All ‐Carbon Centers by Oxidative Ring Contraction
: Oxidative ring contraction of cyclic α‐formyl ketones was facilitated by the action of H2O2 under operationally simple and environmentally benign reaction conditions. The process was highly regioselective... (Source: Organometallic Current)
Source: Organometallic Current - December 3, 2016 Category: Chemistry Tags: All-Carbon Quaternary centers Ring contraction Source Type: blogs
Stereocontrolled Total Syntheses of ( −)‐Rotenone and (−)‐Dalpanol by 1,2‐Rearrangement and SNAr Oxycyclizations
: The total syntheses of ( −)‐rotenone and (−)‐dalpanol have been achieved by a group‐selective, stereospecific 1,2‐shift of an epoxy alcohol and SNAr cyclizations. Three oxacycles are constructed, thus illustrating... (Source: Organometallic Current)
Source: Organometallic Current - December 3, 2016 Category: Chemistry Tags: Natural products Nucleophilic Aromatic Substitution Total synthesis Source Type: blogs
Palladium-Catalyzed Enantioselective α-Arylation of α-Fluoroketones - Journal of the American Chemical Society (ACS Publications)
We report enantioselective coupling of aryl and heteroaryl bromides and triflates with α-fluoroindanones catalyzed by palladium complexes of a BINOL-derived monophosphine and Segphos, respectively. (Source: Organometallic Current)
Source: Organometallic Current - December 2, 2016 Category: Chemistry Tags: alpha arylation Enantioselective Pd Catalyzed Source Type: blogs
Palladium-Catalyzed Enantioselective Intermolecular Coupling of Phenols and Allylic Alcohols - Journal of the American Chemical Society (ACS Publications)
An enantioselective intermolecular coupling of oxygen nucleophiles and allylic alcohols to give β-aryloxycarbonyl compounds is disclosed using a chiral pyridine oxazoline-ligated palladium catalyst under mild conditions. (Source: Organometallic Current)
Source: Organometallic Current - December 2, 2016 Category: Chemistry Tags: Enantioselective Pd Catalyzed Source Type: blogs
New ligands for nickel catalysis from diverse pharmaceutical heterocycle libraries
NatchemNew ligands for nickel catalysis from diverse pharmaceutical heterocycle libraries - pp1126 - 1130Eric C. Hansen, Dylan J. Pedro, Alexander C. Wotal, Nicholas J. Gower, Jade D. Nelson, Stephane Caron& Daniel J. Weixdoi:10.1038/nchem.2587Access to large phosphine ligand libraries has become an essential tool for the application of metal-catalysed reactions industrially, but these existing libraries are not well suited to new catalytic methods based on non-precious metals (for example, Ni, Cu and Fe). The development of the requisite nitrogen- and oxygen-based ligand libraries lags far behind that of the phosphine...
Source: Organometallic Current - December 1, 2016 Category: Chemistry Tags: Heterocycles ligands Ni Catalyzed Source Type: blogs
Rhodium ‐Complex‐Catalyzed Hydroformylation of Olefins with CO2 and Hydrosilane
: A rhodium ‐catalyzed one‐pot hydroformylation of olefins with CO2 , hydrosilane, and H2 has been developed that affords the aldehydes in good chemoselectivities at low catalyst loading. Mechanistic studies... (Source: Organometallic Current)
Source: Organometallic Current - November 30, 2016 Category: Chemistry Tags: Carbon dioxide Hydroformylation Rh Catalyzed Source Type: blogs
An Expedient Total Synthesis of Chivosazole F: an Actin‐Binding Antimitotic Macrolide from the Myxobacterium Sorangium Cellulosum
: A unified strategy for the chemical synthesis of the chivosazoles is described. This strategy is based on two closely related approaches involving the late ‐stage installation of the isomerization‐prone... (Source: Organometallic Current)
Source: Organometallic Current - November 30, 2016 Category: Chemistry Tags: Natural products Total synthesis Source Type: blogs
Alkyl Bromides as Mild Hydride Sources in Ni-Catalyzed Hydroamidation of Alkynes with Isocyanates - Journal of the American Chemical Society (ACS Publications)
(Source: Organometallic Current)
Source: Organometallic Current - November 29, 2016 Category: Chemistry Tags: Hydroamidation Ni Catalyzed Source Type: blogs
