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A Facile Cascade Synthesis of 5,6-Diaryldibenzo[a,e]cyclooctenes from (Z,Z)-1-Aryl-3,5-octadiene-1,7-diynes
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 subseque...
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Published in: | Journal of organic chemistry 1998-06, Vol.63 (13), p.4413-4419 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | 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 32a−c 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. |
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ISSN: | 0022-3263 1520-6904 |
DOI: | 10.1021/jo9802473 |