p-Toluenesulfonic acid-promoted selective functionalization of unsymmetrical arylalkynes: a regioselective access to various arylketones and heterocycles
Regioselective hydration of a wide range of internalalkynes has been afforded in high to good yields by using PTSA in EtOH. The scope of the reaction of alkynes has been delineated. Arylaliphatic alkynes and diarylalkynes were regioselectively hydrated in good to excellent yields and short reaction times when the reaction was achieved under microwave irradiation. Moreover, diarylalkynes, arylenynes
BCl<sub>3</sub>
-Induced Annulative Oxo- and Thioboration for the Formation of C3-Borylated Benzofurans and Benzothiophenes
作者:Andrew J. Warner、Anna Churn、John S. McGough、Michael J. Ingleson
DOI:10.1002/anie.201610014
日期:2017.1.2
form synthetically ubiquitous pinacol boronate esters or used in situ in Suzuki-Miyauracrosscouplings to generate 2,3-disubstituted heteroarenes from simple alkyne precursors in onepot. In a number of cases alkyne trans-haloboration occurs alongside, or instead of, borylative cyclization and the factors controlling the reaction outcome are determined.
MPHT-Promoted Bromocyclization of ortho-Substituted Arylalkynes: Application to the Synthesis of 2-Substituted 3-Bromobenzofurans and -Benzo[b]thiophenes
A convenient and general approach to the synthesis of 2‐substituted 3‐bromobenzofurans and ‐benzothiophenes was developed. The procedure is based on the cyclization of ortho‐substituted arylalkynes in the presence of N‐methylpyrrolidin‐2‐one hydrotribromide (MPHT) as a soft and easy‐to‐handle electrophilic brominating reagent. Under mild reaction conditions, MPHT promoted the bromocyclization of various
A facile access to six‐membered phosphacycle annulated polyaromatic ringsystem through Ag‐catalyzed intramolecular C–P bond formation reaction, from easily accessible phosphine oxides, has been developed, Several new heteroatoms fused π‐conjugated molecules were synthesized from this procedure with their structures confirmed by X‐ray structure analysis.
A method to synthesize benzofurylselenocyanates, benzothienylselenocyanates and indolylselenocyanates via electrophilic selenocyanogen cyclization was established. This sequential process was conducted under mild conditions in a short time. This protocol was successfully applied to late-stage functionalization of bioactive molecules. Notablely, the selenocyanate can be converted into other valuable