W(CO)₅(L)-Catalyzed Tandem Intramolecular Cyclopropanation/Cope Rearrangement for the Stereoselective Construction of Bicyclo[5.3.0]decane Framework

Abstract

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.

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

“…Iwasawa and coworkers [209] discovered a cyclopropanation/DVCPR sequence of alkyne-substituted silyl enol ethers (for example 274 , see Scheme 34) catalyzed by in situ formed W(CO) 5 (tol) upon irradiation to give annulated tricycle 275 . The common mechanism for this type of reaction proceeds via endo - dig cyclization of enynes like 266 to give zwitterionic intermediate 267 .…”

Dearomative [4 + 3] cycloaddition of furans with vinyl-N-triftosylhydrazones by silver catalysis: stereoselective access to oxa-bridged seven-membered bicycles

“…As summarized in Fig. 2, a broad range of β-aryl vinyl-N-triftosylhydrazones with both electron-donating groups (e.g., Me and OMe) and -withdrawing groups (e.g., halogen, CN, NO 2 , CO 2 Et, and CF 3 ) at various positions of aryl ring afforded the corresponding oxa-bridged bicyclic products (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) in 68-85% yield. Similarly, vinyl-Ntriftosylhydrazones bearing an indolyl, thienyl, or furyl group at β-position all e ciently reacted with furan to afford the heteroaryl-substituted products (36-38) in 72-81% yield, whereas a ferrocenyl-substituted substrate led to the product (39) in a moderate yield (45%).…”

“…[1][2][3][4][5][6][7] Over the past few decades, the [4 + 3] cycloaddition between 1,3-dienes and vinylcarbenes has been established as the most promising strategy for the stereoselective synthesis of these complex ring systems, as demonstrated by a variety of complex natural products synthesis. [8][9][10][11][12][13] Major efforts in this arena so far have been dedicated to the use of vinyl diazo compounds, [14][15][16][17][18] propargyl esters, [19][20][21] 4-alkenyl-1,2,3-triazoles, 22,23 enynes, [24][25][26][27] allenes, 28,29 and 7-vinyl-1,3,5-cycloheptatrienes 30 as the sources of vinylcarbene partners to access 1,4cycloheptadienes (Fig. 1a).…”

Bis hin zu einer Symphonie der Reaktivität: Kaskaden mit Katalysen und sigmatropen Umlagerungen

“…Eninisomerisierungen mit elektrophilen Metallkatalysatoren können ebenfalls zur Erzeugung von Divinylcyclopropanen in situ eingesetzt werden (Schema ) 15. Beispielsweise führte die Behandlung des Dienins 26 mit einer katalytischen Menge an PtCl 2 zur Isolierung des bicyclischen Cycloheptadiens 28 ,15a während die Behandlung des Trienins 29 mit einer katalytischen Menge an [W(CO) 6 ] die Isolierung des bicyclischen Cycloheptadiens 31 zur Folge hatte 15b…”