Jie Yan and co-workers from Zhejiang University of Technology, China, have reported on Suzuki-type couplings in water without the use of catalyst and base (Eur. J. PMID:23558135 Org. P(t-Bu)3 Pd G4 site Chem. 2006, 2060.DOI: 10.1002/ejoc.200500915). Both symmetrical and unsymmetrical biaryls could be synthesized by coupling of sodium tetraphenylborate with hypervalent iodonium salts or iodanes under mild reaction conditions. Formula of Perfluorohexyloctane
Synthesis of 1,4-Benzoxazine Scaffolds
A general protocol for the synthesis of 2-alkyl-3,4-dihydro-3-oxo-2H-1,4-benzoxazines 2 has been established by the group of Wei-Min Dai from the Hong Kong University of Science and Technology (Tetrahedron2006, 62, ASAP.DOI: 10.1016/j.tet.2005.12.060). The first step was a reductiveN-alkylation of substituted 2-aminophenols with aromatic aldehydes to obtain the N-alkylated anilines1. Regioselective O-alkylation of 1 with 2-bromoalkanoates furnished acyclic intermediates which showed spontaneous cyclization to 1,4-benzoxazines 2. Higher temperatures (180-200 °C) for the second step were necessary when electron-withdrawing groups were present at the C6 position (R1 = NO2, Cl).
One-Pot Synthesis of 1,2,4-Oxadiazoles
Mehdi Adib and co-workers from University of Tehran have disclosed a three-component one-pot reaction of nitriles, hydroxylamine and aldehydes to give 1,2,4-oxadiazoles (Tetrahedron Lett. 2006, 47, 2965.DOI: 10.1016/j.tetlet.2006.02.102). First the nitrile and hydroxylamine were reacted at 100 °C for 1 min, subsequent addition of aldehyde and irradiation at 150 °C for 3 min under solvent-free conditions gaveoxadiazoles in excellent yields.
Synthesis of Tetracyclic β-Carbolines
The synthesis of thiohydantoin fused tetrahydro-β-carbolines has been investigated by the group of Chung-Ming Sun at the National Chiao Tung University in Taiwan (J. Comb. Chem. 2006, 8, 141. DOI: 10.1021/cc050098j). A soluble polymer-supported strategy using polyethylene glycol (PEG) resin combined with a traceless cyclative cleavage step was applied to achieve products 1 in high stereoselectivity. By employing microwave heating the thermodynamically stable trans diastereomers were obtained preferentially.
