Synthetic studies in the diterpene series. Part VII. Cyclisations of 4,8-dimethyl-1-phenylnon-7-en-4-ol and 2,6-dimethyl-9-phenylnona-2,6-diene and their mechanism
作者:D. Nasipuri、R. Bhattacharya、C. K. Ghosh
DOI:10.1039/j39690000782
日期:——
8-dimethyl-1-phenylnon-7-en-4-ol (I) has been reinvestigated on a quantitative basis. Contrary to a previous report, the major product is not the trans-podocarpa-8,11,13-triene (V) but the hydrophenalene derivative (VII). Oxidation of the mixture with chromic acid, however, enriches the former component as a ketone. Cyclisation of the corresponding diene (IV) gives a preponderance of trans-podocarpatriene (>50%). A
The Pd-catalyzed stereoselective construction of decalins with one-carbon units bearing heteroatoms at the ring junction is described. The Pd-catalyzed cyclization of silyl enol ether resulted in exclusive formation of the cis isomer (89%, >100/1 cis/trans). On the contrary, Pd-catalyzed carboiodination and carboborylation (with oxidative workup) provided products in 56% yield (1/>100 cis/trans) and