%0 Journal Article %A Wang, Kung K. %A Shi, Chongsheng %A Petersen, Jeffrey L. %D 1998 %T A Facile Cascade Synthesis of 5,6-Diaryldibenzo[a,e]cyclooctenes from (Z,Z)-1-Aryl-3,5-octadiene-1,7-diynes %U https://acs.figshare.com/articles/journal_contribution/A_Facile_Cascade_Synthesis_of_5_6-Diaryldibenzo_i_a_i_i_e_i_cyclooctenes_from_i_Z_i_i_Z_i_-1-Aryl-3_5-octadiene-1_7-diynes_sup_sup_/3710670 %R 10.1021/jo9802473.s002 %2 https://ndownloader.figshare.com/files/5801400 %K cyclooctenyl units %K diastereomer %K 1 H NMR spectrum %K presence %K dibenzo %K Facile Cascade Synthesis %K cyclooctene %K cyclooctenyl units exhibits signals %X Sequential treatment of (Z)-3-methyl-2-penten-4-ynal (10) with the allenylborane 2 and 2-aminoethanol furnished 11. The use of 11 for cross-coupling with aryl iodides followed by the KH-induced syn elimination of the coupled adducts 13 provided easy access to a variety of dienediynes 14 for subsequent conversions to dibenzo[a,e]cyclooctenes (sym-dibenzocyclooctatetraenes) 17. By cross-coupling with 1,2- and 1,4-diiodobenzene, it was possible to obtain 19 and 25 having two dienediynyl moieties. It was anticipated that the oligomers 21 and 26 containing multiple dibenzo[a,e]cyclooctenyl units could thus be synthesized. The 1H NMR spectrum of 32 having three dibenzo[a,e]cyclooctenyl units indicates the presence of three diastereomers 32ac in a random statistical distribution of 2:1:1. Similarly, the 1H NMR spectrum of 33 having two dibenzo[a,e]cyclooctenyl units exhibits signals that support the presence of two diastereomers 33a and 33b in a 1:1 ratio. %I ACS Publications