Dearomatizing spirocyclization of thioureas, ureas and guanidines

Electrochemical Oxidative Dearomatization Strategy for Accessing Spiro[4.5]dienones and Derivatives

Electrochemical dearomatization has been recognized as an attractive tool for the rapid construction of structurally diverse molecules. The designed methodology encompasses an eco-friendly and efficient electrochemical approach to synthesizing spiro[4.5]dienones under mild reaction conditions. Furthermore, detailed mechanistic studies strongly bolster our hypothesis and emphasize the role of HFIP in the mechanism. The protocol is scalable and showcases a broad substrate scope with tolerance toward numerous functional groups. Henceforth, this strategy can be deployed as an alternative and sustainable tool for accessing spiro[4.5]dienones.

Enantioselective Total Synthesis of (+)-KB343

A concise total synthesis of the complex guanidinium toxin KB343 is reported traversing through an unusual sequence of chemoselective transformations and strategic skeletal reorganization. The absolute configuration is confirmed through an enantioselective route, and the structures of all key intermediates and the natural product itself are unassailably confirmed through X-ray crystallographic analysis.

Synthesis of Altenuene Backbones through Iodine(III)-Participated Umpolung Diesterification and Insights into the General [1,5]-H Shift in para-Dearomatization of Phenols via Quantum Chemical Calculations

Through PhI(OAc)₂-oxidized dearomatization and diesterification of 3'-hydroxy-[1,1'-biphenyl]-2-carboxylic acids, a series of polycyclic compounds possessing an altenuene backbone were obtained in moderate to good yields. The Umpolung diesterification reaction was completed under mild reaction conditions without an additional nucleophilic reagent. This work offers a concise method for the synthesis of diverse natural altenuene analogues. The mechanism was proposed, and the [1,5]-H shift was studied in isomerization from the ketone-form structure to a phenol employing computational studies.