Asymmetric dearomative [3 + 2] cycloaddition reactions of 3-nitroindoles with vinyl aziridine and vinyl cyclopropanes have been respectively successfully developed in the presence of a chiral box/Pd(0) complex. A series of enantiomerically enriched 3a-nitro-hexahydropyrrolo[2,3-b]indole and 8b-nitrohexahydrocyclopenta[b]indole derivatives containing three contiguous chiral centers are smoothly obtained in high yields with satisfactory regio-, chemo-, and enantioselectivity. Remarkably, the synthetic utility of this process was demonstrated through direct reductive amination and functionalization of the carbon-carbon double bond of the desired products.

A palladium-catalyzed carboxylic acid-directed cross-coupling of an ortho-C(sp 2 ) atom of aromatic acids with aliphatic aziridines to construct the β-arylethylamine skeleton via C−H activation has been developed. The reaction proceeded under mild conditions with great substrate scope. Meanwhile, the β-arylethylamine skeleton in drugs or bioactive compounds could be easily generated in a single step. A catalytic amount of cesium carbonate was crucial to realizing the selective βarylethylamine synthesis.

Direct functionalization of a C−H bond at either the meta or para position by only changing the catalyst system poses a significant challenge. We herein report the [Fe(TPP)Cl]-enabled, selective, C−H difluoromethylation of arenes using BrCF 2 CO 2 Et as the difluoromethylation source, which successfully altered the selectivity from the meta to the para position. A preliminary mechanistic study revealed the iron porphyrin complex not only activated the aromatic ring but also induced para selectivity due to the influence of ligand sterics.

A cascade asymmetric Michael–intramolecular aldol‐lactonization of enals with oxindolyl β,γ‐unsaturated α‐keto esters was developed. An optically pure aminoindanol‐derived triazolium‐based N‐heterocyclic carbene was used as the catalyst. The corresponding desired β‐propiolactone‐fused spiro[cyclopentane‐oxindoles] were obtained in moderate yields with excellent diastereoselectivities and enantioselectivities. Notably, the obtained enantio‐enriched highly functionalized complex molecules contain four contiguous stereocenters, including a spiro all‐carbon center and a quaternary carbon center.magnified image

A Michael-hemiketalization-oxa-Pictet-Spengler cyclization has been developed for the construction of chiral bridged and spiro heterocyclic skeletons with one spiro stereogenic carbon center and two bridgehead carbon centers, utilizing cooperative catalysts of a Takemoto thiourea catalyst and a triflimide. In particular, an oxocarbenium ion acts as a key intermediate for this cyclization reaction. Additionally, biological evaluation of this type of novel structure has revealed obvious antiproliferative activity against some cancer cell lines.