Combining silver- and organocatalysis: an enantioselective sequential catalytic approach towards pyrano-annulated pyrazoles.

Combining silver- and organocatalysis: an enantioselective sequential catalytic approach towards pyrano-annulated pyrazoles† †Electronic supplementary information (ESI) available. CCDC 1035443. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4cc09495f

Combining Silver Catalysis and Organocatalysis: A Sequential Michael Addition/Hydroalkoxylation One-Pot Approach to Annulated Coumarins

A highly stereoselective one-pot procedure for the synthesis of five-membered annulated hydroxycoumarins has been developed. By merging primary amine catalysis with silver catalysis, a series of functionalized coumarin derivatives were obtained in good yields (up to 91%) and good to excellent enantioselectivities (up to 99% ee) via a Michael addition/hydroalkoxylation reaction. Depending on the...

Enantioselective organo-cascade catalysis.

A new strategy for organocatalysis based on the biochemical blueprints of biosynthesis has enabled a new laboratory approach to cascade catalysis. Imidazolidinone-based catalytic cycles, involving iminium and enamine activation, have been successfully combined to allow a large diversity of nucleophiles (furans, thiophenes, indoles, butenolides, hydride sources, tertiary amino lactone equivalent...

Merging Gold and Organocatalysis: A Facile Asymmetric Synthesis of Annulated Pyrroles

The combination of cinchona-alkaloid-derived primary amine and Au(I) -phosphine catalysts allowed the selective C-H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven-membered-ring-annulated pyrrole derivatives in excellent yields and enantioselectivities.

N-methyl pyridinium-p-toluene Sulfonate (NMPyTs) catalyzed synthesis of pyrano[2,3-c]pyrazoles

Abstarct:A simple one-pot synthesis of pyrano[ 2,3-c]pyrazoles was developed by a three-component reaction of various benzaldehydes, malononitrile and 1-phenyl or hydro-3-methyl-1H-pyrazol-5(4H)-one in the presence of N-methyl pyridinium p-toluene sulfonate (NMPyTs) as a catalyst. All of the synthesized compounds were identified by IR, 1H NMR, 13C NMR and mass spectroscopy techniques. In the me...