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。
OBJECTIVE To investigate chiral oxazolidinone directed asymmetric Diels-Alder reaction between dienophile 1 and diene 2 possessing various side chains. METHODS Dienophile 1a-1e and diene 2a-2f were prepared. The Diels-Alder reaction among different substrates were studied. RESULTS The chiral cyclohexene 3-Ⅰ and 3-Ⅱ( 3∶1) were obtained with good selectivity using( S)-4-phenemyl-oxazolidinone containing dienophile 1e and diene 2g. The structures of these adducts were characterized by IR,1HNMR,13 CNMR and HRMS. CONCLUSION The steric hindrance of the 4-substituent in oxazolidinone is the main factor which influences the stereoselectivity of Diels-Alder reaction. The product can be obtained in better selectivity with diene which includes bulky protecting group and longer side chain.