The Intramolecular Diels-Alder Reactions of Silyl Substituted Masked o-Benzoquinones

• Main Authors: Po-Yin Lin, 林泊吟
• Other Authors: Chun-Chen Liao
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/08956305800648412408

碩士 === 國立清華大學 === 化學系 === 89 === Abstract This thesis describes the studies on intramolecular Diels-Alder reactions of masked o-benzoquinones (MOBs). The masked o-benzoquinones, 6-methoxy-4-trimethylsilyl-6-alkenyloxy-2,4-cyclo -hexadienones 49a-c, were generated in situ by the oxidation with DAIB of the corresponding 2-methoxyphenols 44 and alkenols 48. The intramolecular Diels-Alder reactions of MOB 49 provided desired adducts 50 in good yields. Oxidation of 2-methoxyphenols 44 using DAIB, followed by intramolecular Diels-Alder reaction with dienophiles 55, was carried out to produce the tricyclo[4.3.1.03,7]decenones 57 and cis-decalins 58; The tricyclo[4.3.1.03,7]decenones 57 can be converted into cis-decalins 58 via Cope rearrangement in equilibrium. The analyses of the calculation by RHF/STO-3G method suggest that the enthalpy difference between the tricyclo[4.3.1.03,7]decenones 57 and cis-decalins 58 is about 3 Kcal/mol. So the Cope rearrangement process is in equilibrium. Using the vinylmagnesium bromide and cerous chloride complex as addition reagent, addition to tricyclo[4.3.1.03,7]decenones 50 furnished a mixture of the diastereo-selective alcohols 69 and 70.