923987-65-9Relevant academic research and scientific papers
Synthetic studies on and mechanistic insight into [W(CO) 5(L)]-catalyzed stereoselective construction of functionalized bicyclo[5.3.0]decane frameworks
Onizawa, Yuji,Hara, Masahiro,Hashimoto, Takuya,Kusama, Hiroyuki,Iwasawa, Nobuharu
supporting information; experimental part, p. 10785 - 10796 (2010/11/19)
Stereoselective preparation of a variety of synthetically useful functionalized bicyclo[5.3.0]decane derivatives was achieved by tandem cyclization of 3-siloxy-1,3,9-triene-7-yne derivatives based on the electrophilic activation of alkynes catalyzed by [W(CO)5(L)], The reaction proceeded smoothly under photoirradiation, and various substrates were cyclized to give the corresponding bicyclic compounds with up to four chiral centers stereospecifically. Reactions of siloxydienes with a silyl substituent as an equivalent of a hydroxyl group also proceeded with wide generality to afford silyl-substituted bicyclo[5.3.0]decanes, which were highly useful as synthetic intermediates. Stereochemical studies concerning the silyl enol ether moiety suggested that two types of reaction path way for the formation of seven-membered rings were present. The reaction of (Z)-enol silyl ethers proceeded through Cope rearrangement of cis-divinylcyclopropane intermediates, and that of (E)-enol silyl ethers by 1,4-addition of the dienyl tungsten species at the position δ to the metal atom. In the reactions of siloxydiene derivatives with silyl substituents, all possible diastereomers could be synthesized stereoselectively by changing the geometry of the silyl enol ether and enyne moieties.
W(CO)5(L)-catalyzed tandem intramolecular cyclopropanation/cope rearrangement for the stereoselective construction of bicyclo[5.3.0]decane framework
Kusama, Hiroyuki,Onizawa, Yuji,Iwasawa, Nobuharu
, p. 16500 - 16501 (2007/10/03)
Utilizing the biscarbene character of electrophilically activated alkynes, a novel tandem intramolecular cyclopropanation/Cope rearrangement of 3-siloxy-1,3,9-trien-7-ynes catalyzed by W(CO)5(L) for the stereoselective construction of bicyclo[5.3.0]decane framework is achieved. When 3-siloxy-1,3,9-trien-7-ynes were treated with a catalytic amount of W(CO)6 under photoirradiation, bicyclo[5.3.0]decanes were obtained in good yield stereoselectively. In this reaction, the Cope rearrangement of the divinylcyclopropane intermediates, generated by the intramolecular cyclopropanation of 3-siloxy-1,3,9-trien-7-ynes based on the W(CO)5(L)-catalyzed electrophilic activation of alkynes, occurs to give synthetically useful functionalized bicyclo[5.3.0]decane derivatives stereoselectively. Copyright
