Rhodium(I)‐Catalyzed Intramolecular Carbonylative [2+2+1] Cycloaddition of Bis(allene)s: Bicyclo[6.3.0]undecadienones and Bicyclo[5.3.0]decadienones

Abstract

No templates needed: The title reaction makes it easy to construct the bicyclo[6.3.0]undecadienone framework in high yields (see scheme). A template effect is not required to achieve this ring-closing reaction efficiently. The present method can be applied to the construction of bicyclo[5.3.0] and bicyclo[4.3.0] ring systems. Ts = p-toluenesulfonyl.

Exploiting [2+2] cycloaddition chemistry: achievements with allenes

“…98 Oh and co-workers have studied the palladium-catalyzed [2+2] cycloaddition of allenynes 178 and 179, tested previously under microwave conditions, resulting in the formation of the corresponding distal cycloadducts 180 and 181 in good yields (Scheme 93). 54 The optimal conditions for this reaction were found to be the use of Pd(PPh 3 ) 2 Cl 2 (5 mol%) in refluxing toluene, obtaining the corresponding bicyclic compounds without forming any other side product.…”

Rh(I)-Catalyzed Intramolecular Carbonylative [2+2+1] Cycloaddition Reaction: Preparation of Bicyclo[5.3.0]decadienones with Substituted Cyclopentenone Frameworks

“…Namely, the Rh(I)-catalyzed PKTR of 1-substituted-3,7-bis(phenylsulfonyl) nona-1,2,7,8-tetraene derivatives consistently afforded the carbonylative bicyclo[5.3.0] decadienones, similar to those of the 1-unsubstituted ones. 18,19) The 1,9-dimethyl congener also produced the corresponding carbonylative bicyclic compound in good yield. However, it was not the case when the 1,1-dimethyl-3,7-bis(phenylsulfonyl) nonatetraene derivative furnished the [2+ 2] cycloaddition product instead of the desired compound.…”

“…9,10) of enynes (alkyne-alkene). [11][12][13][14][15][16][17] Furthermore, the PKTR of the bis(allene) s 1 (n=1,2) has become a powerful tool for constructing not only the bicyclo[5.3.0]-decadienones 2 (n=1), but also the larger-sized bicyclo[6.3.0]-undecadienone skeletons 2 (n=2) in satisfactory to high yields [18][19][20] (Chart 1). This ring-closing reaction has exclusively occurred at both terminal double bonds of the allenic moieties of 1 (n=1, 2).…”

Creation of Novel Cyclization Methods Using <i>sp</i>-Hybridized Carbon Units and Syntheses of Bioactive Compounds

“…Thus our next efforts were directed toward Rh I -catalyzed [2+2+1] carbonylative cycloaddition of bisallenes. [18][19][20] The initial attempt was performed by treatment of bisallenes 25 with a catalytic amount of [RhCl(CO) 2 ] 2 or [RhCl(CO) dppp] 2 to afford the bicyclo [5.3.0] decadienones 26 in high yields. The largersized eight-membered bicyclo[6.3.0] undecadienones 28 were obtained from 27 in satisfactory-to-high yields.…”

“…The largersized eight-membered bicyclo[6.3.0] undecadienones 28 were obtained from 27 in satisfactory-to-high yields. [18][19][20] A more complicated tricyclic (6/8/5) compound was prepared by this method. 21) Furthermore, it would become interesting to see whether construction of the nine-membered bicyclo [7.3.0]-dodecadienone skeletons 30 20) would be possible using this method.…”