Ring-Closing of 1,7- and 1,8-Enynes of Propargylic O,O-Acetals by Ruthenium-Catalysed Intramolecular Metathesis
作者:Don Antoine Lanfranchi、Christophe Bour、Bastien Boff、Gilles Hanquet
DOI:10.1002/ejoc.201000305
日期:2010.9
Acyclic 1,7- and 1,8-enynes with the alkyne moiety directly connected to the asymmetric carbon of an ethyl acetal have been obtained in two steps from the corresponding aldehydes. Ring-closing metathesis of these enynes delivered the corresponding six- and seven-membered cyclic 1,3-dienes in moderate-to-excellent yields. A competitive ethylene insertion into the alkyne moiety leading to trienes was observed
Type II Intramolecular [5+2] Cycloaddition: Facile Synthesis of Highly Functionalized Bridged Ring Systems
作者:Guangjian Mei、Xin Liu、Chuang Qiao、Wei Chen、Chuang-chuang Li
DOI:10.1002/anie.201410806
日期:2015.2.2
formation of various highlyfunctionalized and synthetically challenging bridged seven‐membered ring systems (such as bicyclo[4.4.1]undecane, bicyclo[4.3.1]decane, bicyclo[5.4.1]dodecane, and bicyclo[6.4.1]]tridecane). This simple, thermal, direct transformation has a broad substrate scope and is high yielding, with high functional‐group tolerance and unique endo selectivity. The highly strained tricyclic