Rhodium(III)-Catalyzed Sequential Cyclization of <i>N</i>-Boc Hydrazones with Propargylic Monofluoroalkynes via C–H Activation/C–F Cleavage for the Synthesis of Spiro[cyclobutane-1,9′-indeno[1,2-<i>a</i>]indenes]
An effective rhodium(III) catalysis for the construction of valuable tetracyclic compounds is described herein. This dominoprocess involving the C–H activation/[3 + 2] annulation/intramolecular Friedel–Crafts reaction sequences of simple and readily available N-Boc hydrazones and propargylic monofluoroalkynes afforded fused tetracyclic spiro[cyclobutane-1,9′-indeno[1,2-a]indenes] in moderate to good
Synthesis of Bridged Polycyclic Ring Systems via Carbene Cascades Terminating in C–H Bond Insertion
作者:Santa Jansone-Popova、Jeremy A. May
DOI:10.1021/ja308305z
日期:2012.10.31
A carbene cascade reaction that constructs functionalized bridged bicyclic systems from alkynyl diazoesters is presented. The cascade proceeds through diazo decomposition, carbene/alkyne metathesis, and C H bond insertion. The diazoesters are easily synthesized from cyclic ketones. Substrate ring size and substitution patterns control the connectivity and diastereomeric preference found in the products.