1,3-Dipolar cycloaddition of diazomethane to chiral azlactones. Experimental and theoretical studies
作者:Carlos Cativiela、María D. Díaz-de-Villegas、JoséI. García、Ana I. Jiménez
DOI:10.1016/s0040-4020(97)00120-8
日期:1997.3
The reaction of (E)-2-phenyl-4-[(S)-2,2-dimethyl-1,3-dioxolan-4-ylmethylen]-5(4H)-oxazolone with diazomethane has been studied under a variety of reaction conditions, and the results compared with those obtained with the corresponding (Z)-isomer. The origin of the high diastereofacial selectivity in the cyclopropane products, observed with both oxazolones, is discussed in the light of theoretical calculations
(E)-2-苯基-4-[(S)-2,2-二甲基-1,3-二氧戊环-4-基亚甲基] -5(4 H)-恶唑酮与重氮甲烷的反应已在多种条件下进行了研究反应条件,并将结果与用相应的(Z)-异构体获得的结果进行比较。根据第一步反应的理论计算,即在半经验(AM1)下进行的重氮甲烷的1,3-偶极环加成,讨论了用两种恶唑酮观察到的环丙烷产物中高非对映选择性的起源。)和从头算起(RHF / 3-21G)级别。两个理论水平正确预测在协同反应途径,导致所述的不对称诱导的方向Δ 1 -吡唑啉。AM1计算还预测了逐步反应路径的存在,该反应会导致开链反应中间体,但从头算结果并不支持。