3- Acyloxy 1,4-enynes, cycloaddition

Shu, X., Li, X., Shu, D., Huang, S., Schienebeck, C. M., Zhou, X., Robichaux, P. J., Tang, W. (2012). Rhodium-catalyzed intra- and intermolecular [5 -I- 2] cycloaddition of 3-Acyloxy-l,4-enyne and aUcyne with concomitant 1,2-acyloxy migration. Journal of American Chemical Society, 134, 5211-5221. 

Synthesis of functionalized resorcinols by rhodium-catalyzed [5+1] cycloaddition of 3-acyloxy-l,4-enynes with CO... 

Synthesis of Functionalized Resorcinols by Rhodium-Catalyzed [5+1] Cycloaddition of 3-Acyloxy-1,4-Enynes with CO... 

In 2010, Malacria and coworkers [17] reported that resorcinol derivatives can be synthesized through a rhodium-catalyzed [5+1] cycloaddition of 3-acyloxy-l,4-enynes with CO in moderate to good yields (Scheme 17.17). Then these highly functionalized resorcinol derivatives could be transformed to the couesponding biochemically important resorcinols simply through saponification. It was found that the Z double bond isomer was not reactive toward the carbonylative cyclization. 

The Au-catalysed intermolecular 4-1-2-cycloaddition reactions of 2-arylynamides with alkenes produced dihydronaphthalenes, whereas the Au-catalysed 2-1-2-1-2-cycloadditions of terminal ynamides with enol ethers produced tetrahydrobenzenes. " The Rh-catalysed 4-1-1- and 5 4-1-cycloaddition reactions of 1,4-enyne esters (7) with CO yielded cyclopentenones (8) and functionalized resorcinols (9), respectively. A key step in these reactions is an acyloxy migration (Scheme 3). ... 

The catalyst-free 5-1-1-cycloaddition reaction between C, A(-cyclic A -acyl azome-thine imines (134) with isocyanides (135) formed imin-l,3,4-oxadiazin-6-one derivatives (136) in high to excellent yields (99%) under mild conditions (Scheme 42). The cobalt-mediated / -pentadienyl (137)/alkyne (138) 5-1-2-cycloaddition reaction yielded /, -cycloheptadienyl complexes (139) under kinetic control. The initial cycloadducts are isomerized to the final >/ -cycloheptadienyl complexes (140) (Scheme 43). The Ru(I)-catalysed intra- and intermolecular 5 4- 2-cycloaddition reactions of 3-acyloxy-l,4-enynes and alkynes produced adducts with highly functionalized seven-membered rings. The reaction sequence includes a 1,2-acyloxy migration. The catalyst-free 5 4- 2-cycloaddition reaction of 2-vinylaziridines with sulfonyl isocyanates in CH2CI2 yielded seven-membered cyclic ureas in high yields (up to 90%). ... 

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