Applications of Intramolecular Cyclopropanations of Chiral Secondary Allylic Diazoacetates
作者:Stephen F. Martin、Michael C. Hillier
DOI:10.1002/jccs.200000004
日期:2000.2
The diastereomeric secondary allylic diazoacetates 6a,b and 8a,b, which were readily prepared from the common intermediate 4, were cyclized in the presence of the achiral catalyst Cu(TBS)2 to furnish mixtures of the adducts 9a,b/10a,b and 12a,b/13a,b, respectively; in these cyclizations, the diastereoselectivity of the reaction was substrate controlled. When 6a,b and 8a,b were cyclized in the presence
由常见中间体 4 容易制备的非对映体仲烯丙基重氮乙酸酯 6a、b 和 8a、b 在非手性催化剂 Cu(TBS)2 存在下环化以提供加合物 9a、b/10a、b 的混合物和 12a,b/13a,b 分别;在这些环化反应中,反应的非对映选择性是受底物控制的。当 6a,b 和 8a,b 在手性催化剂 Rh2[(5S)-MEPY]4 或 Rh2[(5R)-MEPY]4 存在下环化时,如果底物和催化剂相匹配。与使用手性催化剂实现手性烯丙基重氮乙酸酯的非对映选择性环化相关的优势通过合成 25 得到证明,该 25 包含在二萜英格尔 B (14) 中发现的环丙烷亚基。