A C-symmetric -heterocyclic carbene catalysed oxidative spiroannulation of isatin-derived enals: highly enantioselective synthesis of spirooxindole δ-lactones.

A C-symmetric -heterocyclic carbene (NHC)-catalysed activation of isatin-derived enals under oxidative conditions was achieved. The generated α,β-unsaturated acyl azolium species was efficiently trapped by 1,3-dicarbonyl compounds a Michael addition/spiroannualtion cascade, delivering a series of synthetically important spirooxindole δ-lactones with up to 96% enantioselectivity.

N-Butyl-4-hydroxy-1,8-naphthalimide: A new matrix for small molecule analysis by matrix-assisted laser desorption/ionization mass spectrometry.

Rationale: The matrix plays an essential role in defining detection limits and ionization yields of analytes in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis. Small molecule MALDI-MS analyses commonly suffer from the high background interference generated from matrices. Moreover, the inhomogeneous crystallization of some matrices, such as 2,5-dihydroxybenzoic acid (DHB), is to the detriment of the quality or repeatability of detection.

Organocatalyzed Michael-Michael cascade reaction: asymmetric synthesis of polysubstituted chromans.

An enantioselective cascade Michael-Michael reaction between chalcones enolates and nitromethane catalyzed by a bifunctional thiourea is developed. This reaction provides a mild but efficient approach to chiral benzopyrans bearing three consecutive stereocenters in high yields with excellent stereoselectivities, and the benzopyrans can be easily transformed to the corresponding tricyclic product.