A base-promoted tandem approach to bicyclic 8-membered ring ketones.

A base-promoted tandem route toward unprecedented bicyclic 8-membered ring ketones is reported. Under our approach, the targeted products are delivered in high yields from phenylacetylenes and 1,3-diketones. The method has a good scope and gives access to a complex structure that offers a wealth of opportunities for further functionalization.

Palladium-Mediated Oxidative Annulation of δ-Indolyl-α,ß-Unsaturated Compounds toward the Synthesis of Cyclopenta[ b]indoles and Heterogeneous Hydrogenation To Access Fused Indolines.

The cyclopenta[ b]indole moiety represents a key skeletal unit in several natural and synthetic compounds that exhibit diverse biological properties. We described herein a two-step sequence for synthesizing cyclopenta[ b]indoles with great structural diversity in overall yields up to 37%. The key step was a palladium-catalyzed oxidative annulation of 3-alkylindoles (Fujiwara-Moritani reaction). The obtained cyclopenta[ b]indoles were used as substrates in heterogeneous hydrogenation reactions to afford new fused indolines in moderate yields. An acid-catalyzed intramolecular cyclization of three such indolines gave tetracyclic lactams in 89, 90, and 61% yields.