Catalytic Asymmetric 1,3-Dipolar [3 + 6] Cycloaddition of Azomethine Ylides with 2‑Acyl Cycloheptatrienes: Efficient Construction of Bridged Heterocycles Bearing Piperidine Moiety

Conjugated cyclic trienes without nonbenzenoid aromatic characteristic were successfully employed as fine-tunable dipolarophiles in the Cu­(I)-catalyzed asymmetric azomethine ylide-involved 1,3-dipolar [3 + 6] cycloaddition for the first time, affording a variety of bridged heterocycles bearing piperidine moiety in good yield with exclusive regioselectivity and excellent stereoselectivity. 2-Acyl group is the key factor that determines the annulation preferentially through [3 + 6]-pathway, while 2-ester group modulates the annulation through [3 + 2]-pathway

Exoselective 1,3-Dipolar [3 + 6] Cycloaddition of Azomethine Ylides with 2‑Acylcycloheptatrienes: Stereoselectivity and Mechanistic Insight

A highly <i>exo</i>-selective 1,3-dipolar [3 + 6] cycloaddition of azomethine ylides with 2-acylcycloheptatrienes was realized with a Cu­(I)/(<i>S</i>,<i>R</i>_p)-PPF-NHMe complex as the catalyst, leading to a diverse range of bridged piperidines with multiple functionalities in good yield with excellent stereoselectivity control. Theoretical calculations indicated a stepwise mechanism for this <i>exo</i>-selective [3 + 6] annulation, which accounts for the remarkable feature of this annulation: all of the larger substituent groups occupy the axial positions in the six-membered chairlike conformation of the piperidine ring

Sliver-Catalyzed 1,3-Aza-Benzyl Migration of Allyl Alcohol

Carbon migration of alkenyl alcohols has been recognized as an increasingly viable methodology in organic synthesis. Herein, we disclose a silver-catalyzed 1,3-aza-benzyl migration of allyl alcohols by utilizing chelation-assisted selective cleavage of an unstrained C(sp3)–C(sp3) bond. This approach provides an available, efficient, high atom-economic, and environmentally benign procedure, leading to alkylation products with broad substrate scopes and excellent yields. The migration proceeds via a one-pot, two-step process involving a free-state alkyl metal species

Bisannulation of Benzamides and Cyclohexadienone-Tethered Allenes Triggered by Cp*Rh(III)-Catalyzed C–H Activation and Relay Ene Reaction

The diastereoselective bisannulation of <i>N</i>-(pivaloyloxy)­benzamides and cyclo­hexa­dienone-tethered allenes was accomplished through Cp*Rh­(III)-catalyzed C–H activation and relay ene reaction, providing a 3-isoquinolonyl <i>cis</i>-hydrobenzofuran framework with high yields and diastereoselectivities. This reaction tolerates a wide range of functional groups, enabling further conversions to tricyclic and bridged-ring structures. Moreover, the dearomatization modification of phenol-contained bioactive molecule is also elaborated