Ir-Catalyzed Enantioselective Formal C-H Conjugate Addition of Pyrrole and Indoles to α,ß-Unsaturated Carbonyl Compounds.

The chiral Ir(I)-catalyzed intermolecular reaction of N-carbamoylpyrrole and indole derivatives with α,ß-unsaturated carbonyl compounds such as crotonates proceeded with high enantioselectivity. The obtained chirally functionalized pyrroles and indoles are formal C-H conjugate adducts. The reaction mechanism was studied by deuterium labeling experiments.

Enantioselective Cross-Coupling of Electron-Deficient Alkenes via Ir-Catalyzed Vinylic sp2 C-H Alkylation.

A chiral Ir-catalyzed reaction of α-aryl-α,ß-unsaturated amides with ß-substituted acrylates proceeded to give formal conjugate adducts in high yield and ee (up to 99% yield and up to 95% ee). This is the first example of the enantioselective cross-coupling of two different electron-deficient alkenes via vinylic sp2 C-H activation, and polyfunctionalized chiral compounds were obtained.

Dynamic Chirality Control of tropos DPCB-digold Skeleton by Chiral Binaphthyldicarboxylate.

The planar 3,4-diphosphinidenecyclobutene (DPCB) can be remarkably twisted into a C2 -type helical structure by dual coordination of a AuCl moiety. A prompt chirality control of the twisted DPCB skeleton ligated by the digold units affords the enantiopure structure by exchanging the chloride ligands for chiral [1,1'-binaphthalene]-2,2'-dicarboxylate. The chirality of the diaurated 2,2'-bis(diphenylphosphanyl)-1,1'-biphenyl (BIPHEP) system can be controlled prior to that of DPCB. Mixing of a DPCB-bis(chlorogold) complex with the chiral silver salt dynamically leads to a single diastereomer, which was characterized by the (31) P NMR spectrum and the CD couplet patterns in the visible (DPCB) area. The absolute configuration of the singly induced helical structure was assigned by the theoretical CD spectra determined by TD-DFT calculations. Intramolecular alkoxycyclization of hexa-4,5-dien-1-ol catalyzed by the asymmetric DPCB-digold structure were also attempted.