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目的研究含不同噁唑烷酮的亲双烯体1和不同类型侧链取代的双烯体2对不对称Diels-Alder反应的影响。方法制备亲双烯体1a~1e与双烯体2a~2f,并考察不同底物对Diels-Alder反应的影响。结果 (S)-4-苯乙基-噁唑烷酮亲双烯体1e和双烯体2g以最佳选择性得到endo手性环己烯化合物3-Ⅰ和3-Ⅱ(3∶1);所合成的化合物结构经IR、1HNMR、13CNMR和HRMS分析确证。结论噁唑烷酮4位取代基的空间位阻是决定反应立体选择性的主要因素;大位阻保护基和较长侧链的双烯体有利于产物获得较优的选择性。
Aim To study the effect of dienophiles 1 containing different oxazolidones and different types of side chain substituted diolefin 2 on the asymmetric Diels-Alder reaction. Methods The dienophiles 1a ~ 1e and dienophiles 2a ~ 2f were prepared and the effects of different substrates on the Diels-Alder reaction were investigated. As a result, (S) -4-phenethyl-oxazolidinone dienophile 1e and dienophile 2g gave endo chiral cyclohexene compounds 3-I and 3-II (3: 1) The structures of the synthesized compounds were confirmed by IR, 1HNMR, 13CNMR and HRMS. Conclusion The steric hindrance of the 4-substituent of oxazolidinone is the main factor that determines the stereoselectivity of the reaction. The diolefin with bulky steric hindrance and longer side chain is favorable for obtaining better selectivity of the product.