TY - DATA T1 - AlCl3‑Catalyzed Ring Expansion Cascades of Bicyclic Cyclobutenamides Involving Highly Strained Cis,Trans-Cycloheptadienone Intermediates PY - 2015/04/29 AU - Xiao-Na Wang AU - Elizabeth H. Krenske AU - Ryne C. Johnston AU - K. N. Houk AU - Richard P. Hsung UR - https://acs.figshare.com/articles/journal_contribution/AlCl_sub_3_sub_Catalyzed_Ring_Expansion_Cascades_of_Bicyclic_Cyclobutenamides_Involving_Highly_Strained_i_Cis_i_i_Trans_i_Cycloheptadienone_Intermediates/2172187 DO - 10.1021/jacs.5b02561.s003 L4 - https://ndownloader.figshare.com/files/3806113 KW - AlCl KW - cyclobutenamide KW - ci KW - evidence KW - tetracyclic molecules KW - bicyclic KW - cascade reactions KW - electrocyclic ring opening KW - DFT calculations KW - Bicyclic Cyclobutenamides KW - ketone N2 - We report the first experimental evidence for the generation of highly strained cis,trans-cycloheptadienones by electrocyclic ring opening of 4,5-fused cyclobutenamides. In the presence of AlCl3, the cyclobutenamides rearrange to [2.2.1]-bicyclic ketones; DFT calculations provide evidence for a mechanism involving torquoselective 4π-electrocyclic ring opening to a cis,trans-cycloheptadienone followed by a Nazarov-like recyclization and a 1,2-alkyl shift. Similarly, 4,6-fused cyclobutenamides undergo AlCl3-catalyzed rearrangements to [3.2.1]-bicyclic ketones through cis,trans-cyclooctadienone intermediates. The products can be further elaborated via facile cascade reactions to give complex tri- and tetracyclic molecules. ER -