Synthesis of <i>N</i>,<i>O</i>-Spiroacetals and α-Arylfurans via Pd-Catalyzed Aerobic Oxidative 2,5-Aminoarylation and α-Arylation of <i>N</i>-[3-(2-Furanyl)propyl]-<i>p</i>-toluenesulfonamides with Boronic Acids
作者:Zhiqiang Wang、Wenkun Luo、Lin Lu、Biaolin Yin
DOI:10.1021/acs.joc.8b01393
日期:2018.9.7
Unsaturated N,O-spiroacetals and α-arylfurans were synthesized via palladium-catalyzed aerobic oxidativecouplingreactions between N-[3-(2-furanyl)propyl]-p-toluenesulfonamides and boronic acids, with KF and KOAc as the respective additives. These reactions involve an unprecedented dearomatizing 2,5-aminoarylation and a direct α-arylation of furan rings, respectively, with O2 as the terminal oxidant
The palladium(0)‐catalyzed direct construction of bicyclic heterocycles is described. Treatment of propargyl bromides that have nucleophilic functional groups connected by two or three carbon atoms with catalytic [Pd(PPh3)4] affords bis‐cyclization products in good yields. The desired bicyclic heterocycles can be obtained selectively when using substrates with appropriate nucleophilic groups. We also
Conformational preferences of oxy-substituents in butenolide–tetrahydropyran spiroacetals and butenolide–piperidine spiro-N,O-acetals
作者:Sébastien Naud、Sarah J. Macnaughton、Bryony S. Dyson、Daniel J. Woollaston、Jonathan W. P. Dallimore、Jeremy Robertson
DOI:10.1039/c2ob06849d
日期:——
of a series of oxy-substituted butenolide spiroacetals and spiro-N,O-acetals by oxidative spirocyclisation of 2-[(4-hydroxy or 4-sulfonamido)butyl]furans. The axial–equatorial preference of each oxy-substituent is investigated (NMR) by an acid-catalysed thermodynamic relay of configuration between the spiro- and oxy-centres. The axial site is preferred for most oxy-substituents at synthetically useful
The palladium-catalyzed domino cyclization of propargyl bromides having two nucleophilic functional groups is described. Treatment of 1,7-diamino-5-bromohept-3-yne derivatives with catalytic Pd(PPh3)(4) in the presence of NaH in MeOH gives the 2,7-diazabicyclo[4.3.0]non-5-enes in good yields. Interestingly, the regioselectivity of the reaction is completely controlled by the relative reactivity of the amine functional groups, irrespective of the position of the nucleophiles. The malonate derivative also undergoes domino cyclization to produce a hexahydroindole derivative.