[Seasonal Variations and Source Apportionment of Carbonaceous Components in Luoyang: Implication for Brown Carbon Contribution].

A total of 98 samples were collected to analyze the seasonal variation and source apportionment of carbonaceous components, especially brown carbon (BrC), of PMin Luoyang during 2018-2019. The concentrations of organic carbon (OC) and elemental carbon (EC) ranged from (7.04±1.

Tunable stereoselective alkene synthesis by treatment of activated imines with nonstabilized phosphonium ylides.

A broad range of readily accessible N-sulfonyl imines undergo olefination reaction with nonstabilized phosphonium ylides under mild conditions to afford an array of both Z- and E-isomers of 1,2-disubstituted alkenes, allylic alcohols, and allylic amines in good yields and with greater than 99 : 1 stereoselectivity.

Controllable stereoselective synthesis of trisubstituted alkenes by a catalytic three-component reaction of terminal alkynes, benzylic alcohols, and simple arenes.

The acid-catalyzed three-component reaction of terminal alkynes, benzylic alcohols, and simple arenes provides convenient and atom-economic access to an array of both Z- and E-isomers of trisubstituted alkenes with excellent stereoselectivity by switching reaction temperature and acidic catalysts.