Over the past years, the metal‐catalyzed dearomative cycloaddition of 3‐nitroindoles and 2‐nitrobenzofurans have emerged as a powerful protocol to construct chiral fused heterocyclic rings. However, organocatalytic dearomative reaction of these two classes of heteroarenes has become a long‐standing challenging task. Herein, we report the first example of phosphine‐catalyzed asymmetric dearomative [3+2]‐cycloadditio of 3‐nitroindoles and 2‐nitrobenzofurans, which provide a new, facile, and efficient protocol for the synthesis of chiral 2,3‐fused cyclopentannulated indolines and dihydrobenzofurans by reacting with allenoates and MBH carbonates, respectively through a dearomative [3+2]‐cycloaddition.

The development of electron-demand disfavored [4 + 2] cycloaddition of two electron-deficient reacting partners poses a considerable challenge. An enantioselective aza-[4 + 2] cycloaddition of electron-deficient N-sulfonyl-1-aza-1,3-dienes is possible with vinyl ketones via phosphine catalysis, which provides facile access to a wide range of enantioenriched trifluoromethylated tetrahydropyridines in up to 97% yield with 97% ee and >20:1 dr. The mechanistic study indicated that this cycloaddition proceeds via a tandem intermolecular aza-Rauhut-Currier/intramolecular aza-Michael addition reaction.

An efficient procedure for the synthesis of 2-arylquinazolines from N′-arylbenzimidamides has been developed under transition-metal-free conditions.

A novel approach for the synthesis of 2,3-diarylquinazolinones using iron as catalyst is described. Various 2-nitro-N-arylbenzamides reacted with benzylic alcohols to selectively give the corresponding products in the absence of external oxidant or reductant.

An efficient ferrocene-derived bifunctional phosphine-catalyzed enantioselective oxa-[4+ +2] cycloaddition of a-substituted allenones with ab road range of enones is investigated for the preparation of stereodefined dihydropyrans in good to excellent yields (up to 99 %) and excellent enantioselectivity (up to 99 % ee). Furthermore, a series of valuable chiral polyheterocyclic frameworksc an be efficiently achieved in good yields with excellente nantioselectivities.Dihydropyrans and pyrans have attracted wide synthetic interest due to their rich appearance as important skeletons of bioactive active molecules and naturalp roducts [1] .A mongt hem, trifluoromethylated dihydropyrans are an important class of trifluoromethylated heterocycles that are featured in av arietyo f biologically andp harmaceutically active molecules, for instance,a ntimalarial agents III [2] and NK-1 receptora ntagonist IV.[3] Despite the progress that has made in the synthesis of dihydropyrans and pyrans using metal-free catalysts such as Nheterocyclic carbenes [4] and amines, [5] methods of synthesizing optically active dihydropyrans with ac hiral carbon center bearing aC F 3 group are very rare [6] and are therefore highly desirable.Recently,L ua nd coworkers [7a] described the first example of generating chiral pyranst hrough ad ipeptide-based bifunctional phosphine (P0)-catalyzed annulation reaction between allenones with b,g-unsaturated a-ketoesters (Scheme 1a). Subsequently,L ue tal.[7b] extended this protocol through the introductiono facyano-group at the a-position of the chalcone by the use of am uch simple l-valine-derived bifunctional phosphine (P1)( Scheme 1b). As part of our ongoing interest in the enantioselectives ynthesis of enantioenriched trifluoromethylated building blocks, [8, 9f-h] we have developed as eries of bior multi-functional phosphine catalysts [9] that demonstrated good performance in enantioselective Rauhut-Currier reactions, [9a-e] allylation reactions [9f] and asymmetric cycloaddition. [9h,i] Followingt his, we becamei nterested in the asymmetric phosphine-catalyzed oxo-[4+ +2] annulation of perfluoroalkylated a,b-enones and allenones, which could produce av ariety of valuablec hiralp erfluoroalkylated dihydropyrans. [10] We report herein an efficient ferrocene-derived bifunctionalp hosphine catalyst P5,w hich displays high performance in the asymmetric oxo-[4+ +2] cycloaddition of a-substituted allenones with a broad range of enones, producing diverse valuable chiral functionalized 3,4-dihydropyrans in good yields and high enantioselectivity (Scheme 1c).b-Trifluoromethylated enone 1f and allenone 2a weres elected as model substrates to screen the reactionc onditions (Table 1) using the chiralp hosphine catalysts (Figure 1). Gratifyingly,c atalyst P1,u sed in Lu's previousw ork, [7b] could indeed catalyzet he cycloadditionr eaction in toluene at room temperature, giving the desired trifluoroalkylated 3,4-dihydropyran in 95 %y ield with acceptable ee (Table 1, entry 1). The replacement o...