title: Unusual regio- and stereo-selectivity in Diels-Alder reactions between bulky N-phenylmaleimides and anthracene derivatives.
abstract: Unusual regio- and stereo-selectivity in Diels-Alder (D-A) reactions were achieved between bulky N-phenylmaleimides and anthracene derivatives. Using multiple substituents with steric hindrance on both diene and dienophile, a noticeable shift toward 1,4-addition was successfully obtained. The substrate scope in this reaction was broad and the highest yield of anti-1,4-adducts was over 90%. Novel structures of anti-1,4-adducts were confirmed by single crystal X-ray diffraction analysis. This study not only provides the first reported method of synthesizing anti-1,4-adducts and achieving otherwise unattainable regio- and stereo-selectivity, but also elucidates the importance of combining the steric effects of two reactants to shift products toward 1,4-adducts. Moreover, the resulting 1,4-adducts could be further functionalized through their halogen groups via carbon-carbon coupling reactions.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Center for Soft Matter Science and Engineering, Key Lab of Polymer Chemistry & Physics of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China. ygma@pku.edu.cn.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Erdong
authors.initials: E
authors.lastname: Yao
authors.forename: Chi
authors.initials: C
authors.lastname: Xu
authors.forename: Xiao
authors.initials: X
authors.lastname: Meng
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Ma