A study of palladium catalyzed intra/intermolecular cascade cross coupling/cyclizations involving bicyclopropylidene.
The compounds [3-(2-Bromocyclohex-2-enyloxy)prop-1-ynyl]-tert-butyl-dimethylsilane 3, [4-(2-bromocyclohex-2-en-1-yloxy)but-2-yn-1-yloxy]tert-butyldimethylsilane 5 and dimethyl 2-(2-bromocyclohex-2-enyl)-2-(3-(tert-butyldimethylsilanyl)prop-2-ynyl)malonate 9 were prepared and subjected to palladium-catalyzed intra-intermolecular cascade cross couplings incorporating bicyclopropylidene 10 under two types of conditions. In the presence of Pd(OAc)2, PPh3 and K2CO3 in acetonitrile at 80 °C, the products were indene analogues, cross-conjugated tetraenes 11, 12 and 13, respectively. The corresponding spirocyclopropanated tricycle 16 in dimethylformamide at 110 °C was obtained, albeit in low yield (24%), and observed as an equimolar mixture of diastereomers, whereas 14, 15 were not fully isolated.
Department of Chemistry, Faculty of Arts &Science, Nigde University, Nigde 51240, Turkey. ademircan@gmail.com.
Aydin
A
Demircan
D002384:Catalysis; D003500:Cyclization / Q000187:drug effects; D003512:Cyclohexanones / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D013237:Stereoisomerism
C540508:2-bromocyclohexanone; D003512:Cyclohexanones; D012821:Silanes; C103256:tert-butyldimethylsilane; D010165:Palladium