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Date: 26-11-2019
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Date: 1-8-2019
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A Diels-Alder
A Diels-Alder approach to to tricyclic cedrene skeleton was reported by Breitholle et.al., (Can. J. Chem., 54, 1991 (1976) (Figure 8.8). Alkylation of cyclobutadiene to the requisite chain gave 8.8A after equilibration. The DA reaction proceeded in 36% yield to give a mixture of isomers. The ketone 8.8B did not undergo ring expantion with diazomethane. The ring expansion was finally achieved via the methylene amine 8.8C via diazotisation. The fact that two ring expansion products 8.8D and 8.8E were formed with 8.8D as the major product suggests that the amine 8.8F was the major isomer.
Figure 8.8
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جامعة الكفيل تحتفي بذكرى ولادة الإمام محمد الجواد (عليه السلام)
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