As ynergistic catalytic method combining photoredox catalysis,hydrogen-atom transfer,and proton-reduction catalysis for the dehydrogenative silylation of alkenes was developed. With this approach,ahighly concise route to substituted allylsilanes has been achieved under very mild reaction conditions without using oxidants.T his transformation features good to excellent yields,o perational simplicity, and high atom economy.B ased on control experiments, apossible reaction mechanism is proposed. Scheme 1. Strategies for the synthesis of substituted allylsilanes.

Difluoroalkylated diarylmethanes with biological and pharmacological potentials were synthesized from para-quinone methides (p-QMs) and difluoroalkylating reagents via a visible light photocatalysis strategy. Mechanism studies showed that the excited photocatalyst, *fac-Ir(ppy)3, was primarily quenched by p-QMs and the generated diarylmethane radical intermediates then underwent a radical-radical cross-coupling reaction with difluoroalkyl radicals. This reaction features mild conditions, high efficiency and wide functional group compatibility.

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.

A Lewis acid catalyzed [3+4]-annulation reaction between cyclopropane 1,1-diesters and anthranils has been developed. This annulation consists of a reaction sequence involving ring-opening/aromatization/nucleophilic addition. Thereinto, aromatization is the driving force for this annulation. Using this reaction, a series of 8-oxa-1-azabicyclo[3.2.1]octanes can be prepared conveniently with excellent diastereoselectivity.

Highly enantioselective chiral bifunctional thiourea catalyzed asymmetric tandem reactions for synthesis of substituted tetrahydroquinolines are described. Substituted tetrahydroquinolines were given in good yields (up to 98%), high enantioselectivities (up to >99% ee), and diastereoselectivities (up to 20:1 dr).

Cascading like dominos: An efficient and highly enantioselective synthesis of 2,3,4-trisubstituted tetrahydroquinolines through cascade aza-Michael-Michael reactions was developed. Tetrahydroquinolines were obtained in excellent yields, high enantioselectivities, and good diastereoselectivities, and could be easily transformed into ring-fused tetrahydroquinolines (see scheme).

An organocatalytic vinylogous Friedel-Crafts alkylation-initiated formal [2+2] cycloaddition was successfully developed based on tandem iminium-enamine activation of enals. Transformable pyrrole-functionalized cyclobutanes with three contiguous stereocenters were readily obtained with excellent levels of regio-, diastereo- and enantiocontrol.

A variety of axially chiral biaryldiols were synthesized in good yields with excellent atropo-enantioselectivities through construction of axially chiral indoles catalyzed by asymmetric hydrogen-bond donors. In addition, the new axially chiral compounds were proved to be efficient and practical catalysts for asymmetric catalysis. The strategy not only provides a novel method to synthesize axially chiral compounds but also extends the scope of chiral catalysts.