100848-86-0Relevant articles and documents
Catalytic Enantioselective Desymmetrization of Norbornenoquinones via C(sp2)-H Alkylation
Sarkar, Rahul,Mukherjee, Santanu
, p. 6160 - 6163 (2016/12/09)
The enantioselective Diels-Alder (DA) reaction with monosubstituted p-benzoquinones is an unmet challenge. A new approach for the enantioselective synthesis of monosubstituted quinone-DA adducts is presented based on C(sp2)-H alkylative desymmetrization of meso-DA adducts. Catalyzed by a tertiary amino-thiourea derivative, this reaction utilizes nitroalkanes as the alkylating agents and generates densely functionalized products bearing at least four contiguous stereogenic centers remote from the reaction site with excellent enantioselectivities.
Benzoquinones and Related Compounds. Part 5. Nuclear Magnetic Resonance Study of the Conformation in Solution of Some Diels-Alder Adducts between 1,4-Benzoquinones and Cyclopentadiene
Al-Hamdany, Raad,Bruce, J. Malcolm,Heatley, Frank,Khalafy, Jabbar
, p. 1395 - 1400 (2007/10/02)
The Diels-Alder reaction of cyclopentadiene with the 5,6-double bond of benzyl-, α-hydroxybenzyl-, and α-acetoxybenzyl-1,4-benzoquinone, and of 1-hydroxy-1-phenyl-, 1-phenyl-, and 1-hydroxy-indan-4,7-quinone gives in each case a pair of diastereoisomeric endo adducts.For those which carry a phenyl group, the chemical shift of one of the norbornene olefinic protons in one member of each pair is significantly different from that of the corresponding proton in the other member.The conformational significance of this effect is discussed.Proton longitudinal relaxation and nuclear Overhauser relaxation techniques are used to show that the cyclopentadiene endo monoadducts of 1,4-benzoquinone and α-hydroxybenzyl-1,4-benzoquinone prefer to adopt an 'open' rather than a 'closed' conformation.
