An Improved Synthesis of Cyclic Dialkynes
- 1 January 1993
- journal article
- research article
- Published by Georg Thieme Verlag KG in Synthesis
- Vol. 1993 (06) , 558-560
- https://doi.org/10.1055/s-1993-25901
Abstract
An improved synthesis of 1,7-cyclododecadiyne 17 (35%), 1,7-cyclotridecadiyne 18 (65%), 1,8-cyclotetradecadiyne 19 (85%), 1,8-cyclopentadecadiyne 20 (65%), 1,9-cyclohexadecadiyne 21 (55%), 1,10-cyclooctadecadiyne 22 (48%) and 1,12-cyclodocosadiyne 23 (27%) is reported. This is achieved by treating the dilithium salts of diterminal dialkynes with α,ω-dihalogenides. As side products, tetraynes are isolated in yields of 1-5%. Furthermore, the synthesis of 6-isopropylidenethiacyclodeca-3,8-diyne (24) and [10]orthocyclophane-2,8-diyne 29 is reported. The reaction of 24 with CpCo(CO)2 yields a [2.2](2,5) thiophenophane derivative 30 while 29 gives an intramolecular cyclobutadiene complex 31.Keywords
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