Abstract Phosphonium enolates are key intermediates of phosphine-catalyzed reactions extensively used in current organic synthesis for construction carbon–carbon and carbon–heteroatom bonds. Herein, general methods increasing the rates, chemo- stereoselectivity on basis effects anchimeric assistance involving formation phosphonium discussed.

Photochemistry has been developed as a powerful tool for organic transformations, such photoredox catalysis, photocycloaddition, and photoisomerization. Traditional photochemistry relies on molecular photosensitizers. Recently in Chem Catalysis, Weiss colleagues applied semiconductor nanoparticles photosensitizers to drive [2 + 2] cycloaddition of aryl-conjugated dienes with high chemo- ...

An oxidative Pd-catalyzed intra-intermolecular dioxygenation of (aza-)alkenols has been reported, with total regioselectivity. To study the stereoselectivity, different chiral ligands as well hypervalent-iodine compounds have compared. In particular, by using a C-6 modified pyridinyl-oxazoline (Pyox) ligand and hypervalent iodine bearing an aromatic ring, excellent enantio- diastereoselectivity...

An asymmetric Claisen rearrangement using Oppolzer’s camphorsultam was developed. Under thermal conditions, a geraniol-derived substrate underwent the rearrangement with good stereoselectivity. The absolute configuration of the newly formed all-carbon quaternary stereocenter was confirmed by the total synthesis of (+)-bakuchiol from the rearrangement product.

Cross-dimerization of various terminal alkynes with different bulky terminal alkynes such as triisopropylsilylacetylene and 1-trimethylsilyloxy-1,1-diphenyl-2-propyne efficiently proceeds in the presence of a rhodium catalyst system to produce the corresponding (E)-enynes with high regio- and stereoselectivity.

A highly enantio- and diastereoselective [4+1] annulation between in situ generated ammonium ylides and o-quinone methides for the synthesis of a variety of 2,3-dihydrobenzofurans has been developed. The key factors controlling the reactivity and stereoselectivity were systematically investigated by experimental and computational means and the energy profiles obtained provide a deeper insight i...

A practical protocol for the preparation of (5Z)-2-alkylthio-5-arylmethylene-1-methyl-1,5-dihydro-4H-imidazol-4-one derivatives is reported. The new compounds were obtained in good yield and stereoselectivity in two steps, namely a solvent-free Knoevenagel condensation under microwave irradiation, followed by an S-alkylation reaction with various halogenoalkanes.