苯乙炔(4a)於鈀錯合物催化下可進行三聚合反應，合成(1Z)-1,3-二苯基-2-苯乙炔基-1,3-丁二烯(Z-7a)，利用此合成方法，已製備15種三聚合衍生物，此方法提供很高的位向選擇性及不錯的產率。化合物Z-7d與Z-7o的結構及立體化學已經由X-ray單晶繞射分析確定。據我們所知，這是第一個例子由末端炔直接進行三聚合反應得到此角形骨架的二烯炔化合物，因此我們就反應的位向選擇性及限制的因素進行研究。
鈀金屬催化劑、胺鹼、溶劑及溫度於此反應中均扮演關鍵的角色。反應條件已調整至最佳化：將苯乙炔(4a)、二氯雙(三苯基磷)鈀(II)、三苯基磷、三乙胺及碘化亞銅，溶於乙腈溶劑，在75-80 ºC下，經過約40-48小時，可得到94%的(1Z)-1,3-二苯基-2-苯乙炔基-1,3-丁二烯(Z-7a)。根據結構的相關性，推測1,3-雙取代烯炔化合物6是關鍵的中間產物，可進一步在炔的官能基上，經由氫炔化加成反應(hydroalkynylation)，形成產物7。末端炔上芳香環取代基若具有較豐富的電子特性，反應效果較佳，而當推電子基團位於苯環之對位時，對位向選擇性有明顯的影響，無法得到產物7確切的E/Z比。另外，當炔類化合物具有立體較大的取代基團時，仍然以Z-7為主要位向異構物，但會產生較多的烯炔化合物6與E-7產物。

Various 1,3-diaryl-2-arylethynyl-1,3-butadienes 7 have been generated by the Pd-catalyzed trimerization of arylalkynes 4. Based on this synthetic method, fifteen dienyne derivatives have been prepared in 23-94% yields. This procedure provides high regioselectivity to generate adducts Z-7 in moderate to excellent yields. Their structures and stereochemistry have been confirmed by the X-ray crystal analyses. To the best of our knowledge, this is the first example to generate a dienyne with this skeleton by trimerization of a terminal alkyne. The scope, limitations and regioselectivity of this reaction have been investigated.
Systematic studies of the reaction conditions revealed that palladium catalyst, base, solvent and temperature all play key roles. The reaction conditions have been optimized. Upon heating phenylacetylene (4a) in CH3CN at 75-80 ºC with a mixture of PdCl2(PPh3)2, PPh3, NEt3 and CuI, angular dienyne (1Z)-1,3-diphenyl-2-phenylethynyl-1,3-butadiene (Z-7a) can be obtained with high regioselectivity in 94% yield. According to the correlation of the structure, an aryl-substituted but-3-en-1-ynes 6 is the key intermediate for the further hydroalkynylation to form dienyne 7. Generally, alkynes furnished corresponding adducts 7 with Z-regioselectivity. An electron-donating group only at the para-position of the phenyl substituents of arylethynes had a major influence on regioselectivity, and the E/Z ratio of dienynes could not be accurately reported. In addition, angular trimerization of an arylalkyne with a sterically congestive substituent led to the formation of a significant amount of intermediate 6 as well as the E-adduct.

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