Vogt P F, Miller M J, Mulvihill M J, Ramurthy S, Savela G C, Ritter A R
Department of Chemistry and Biochemistry, University of Notre Dame, Indiana 46556, USA.
Enantiomer. 1997;2(5):367-80.
The diastereoselectivities of several chiral acylnitroso dienophiles (9a-h, 12 and 15) derived from optically pure, N-protected alpha-amino hydroxamic acids (2a-h, 4 and 7) were determined in an intermolecular hetero Diels-Alder reaction with cyclopentadiene. The diastereomeric excesses ranged from 0 to 72%. Hydroxamic acids with polar functionality were examined extensively to determine the effect of hydrogen bonding on the cycloaddition. The largest increase in diastereoselectivity was observed with increasing the steric bulk at the alpha-position of the hydroxamic acids and not with potential hydrogen bonding interactions. The cycloadditions afforded synthetically useful quantities of functionally rich, enantiomerically pure heterocycles (10a-h, 11a-h, 13, 14, 16 and 17), which have been elaborated into a variety of biologically interesting products.
在与环戊二烯的分子间杂狄尔斯-阿尔德反应中，测定了由光学纯的N-保护的α-氨基异羟肟酸（2a-h、4和7）衍生的几种手性酰基亚硝基亲双烯体（9a-h、12和15）的非对映选择性。非对映体过量范围为0%至72%。对具有极性官能团的异羟肟酸进行了广泛研究，以确定氢键对环加成反应的影响。随着异羟肟酸α位空间位阻的增加，而非潜在的氢键相互作用，非对映选择性有最大程度的提高。环加成反应得到了合成上有用量的功能丰富、对映体纯的杂环化合物（10a-h、11a-h、13、14、16和17），这些化合物已被转化为多种具有生物学意义的产物。
