1-Phenyl-1, 3-pentadiyne(PPD) was photolyzed in 2, 3-dimethyl-2-butene(DMB) to obtain a site specific [2+2] type 1:1 photoadduct 1. Irradiation of PPD with unsymmetrical olefins such as ethyl vinyl ether [EVE] and acrylonitrile[AN] yields site specific and regiospecific [2+2] type 1:1 photoadducts [$\underline{2}$ and $\underline{6}$] and 1:2 photoadducts[$\underline{3}$-$\underline{5}$ and $\underline{7}$-$\underline{9}$] which are bicyclo [2.2.0.] hexane derivatives having three stereoisomers. The 1:1 photoadducts are the primary photoproducts and 1:2 photoadducts are the secondary photoproducts because the 1:1 photoadducts are initially formed and prolonged irradiation of the solution results in the formation of 1:2 photoadducts. the regiochemistry of 1:1 photoadducts [$\underline{3}$-$\underline{5}$ and $\underline{7}$-$\underline{9}$] is determined by $^1H$-NMR spectrum and results of the regiochemistry of 1:2 photoadducts. The regiochemistry of 1:2 photoaddcuts is determined by mass spectral fragmentation patterns of thermally rearranged products of 1:2 adducts and NOE studies. The stereochemistry of 1:2 adducts is also identified by NOE studies. The formation pathway of these adducts is proposed.
1,4-Diphenyl-1, 3-butadiyne(DPB) was photolyaed in DMB to obtain three photoadducts($\underline{12}$-$\underline{14}$). the photoadducts $\underline{12}$ and $\underline{13}$ are initially formed and prolonged irrdiation of the solution results in decrease of $\underline{12}$ and formation fof $\underline{14}$ indicating that $\underline{14}$ is a secondary photoproduct of $\underline{12}$. At initial stage of photolysis of DPB with EVE yields a regiospecific [2+2] type photoadduct $\underline{15}$ as the primary photoproduct. Extended irradiation of the solution results in the formation of 1:2 photoadducts ($\underline{16}$ and $\underline{17}$). The secondary photoadduct(s) of $\underline{15}$ is (are) very unstable at room temperature and thermally rearranged products ($\underline{16}$ and $\underline{17}$) are isolated. The regiochemistry of $\underline{15}$ is determined by analyzing coupling patterns in the $^1H$-NMR spectrum of the hydrogenation product, and that of $\underline{16}$ and $\underline{17}$ is determined by fragmentation patterns of mass spectra. Quenching experiments suggest that all of the photoreactions carried out in this investigation proceed via triplet excited states. A plausible photoreaction mechanism involving diradical intermediates is proposed.
1-페닐-1,3-펜타디인과 2,3-디메칠-2-부텐을 광반응시키면 [2+2] 형태의 1:1 광생성물인 1이 얻어진다. 1-페닐-1,3-펜타디인과 에칠 비닐 에테르, 아크릴로니트릴과 같은 비대칭 올레핀을 광반응 시키면 위치특이성을 가지는 1:1 (2, 6) 과 1:2 (3-5, 7-9) 광생성물들이 얻어진다. 이 1:2 광생성물들은 입체이성질체들로서 이들의 정확한 구조는 NOE 실험을 통하여 밝혔다. 이 광생성물들의 위치특이성은 수소핵자기공명 스펙트럼이나 열분해 생성물의 질량분석법등을 통하여 규명되었다. 광 조사 시간에 따른 상대적인 광생성물의 농도 변화를 통하여 1:1 광생성물은 1차 생성물이고 1:2 광생성물은 2차 생성물임을 알 수 있었다. 이러한 광생성물의 생성과정을 자세히 연구하였다. 1,4-디페닐-1,3-부타디엔과 2,3-디메칠-2-부텐을 광반응시키면 세개의 광생성물 12, 13, 14이 얻어진다. 생성경로에 대한 자세한 연구를 진행하여 12와 13은 1,4-디페닐-1,3-부타디엔의 삼중항 상태에서 생성된 1차 생성물이며 14는 12의 삼중항 상태에서 생성된 2차 광생성물임을 확인하였다. 1,4-디페닐-1,3-부타디엔과 에칠 비닐 에테르의 초기 광반응에서는 위치특이성을 가지는 광생성물 15가 1차 생성물로 생성된다. 계속하여 광반응 시킬 때 얻어지는 2 차 생성물은 실온에서 불안정하여 열분해 생성물인 16과 17이 얻어진다. 삼중항 소광 실험을 통하여 이 연구에서 다루어진 모든 반응은 삼중항 여기상태를 거쳐 진행함을 알 수 있었다. 디라디칼 중간체를 포함하는 광반응 메카니즘을 제시하였다.
