65698-22-8Relevant articles and documents
First total synthesis of palmarumycin C6 based on double oxa-michael addition of 1,8-dihydroxynaphthalene to 3-bromo-1-indenone
Tsukamoto, Hirokazu,Nomura, Yumi,Doi, Takayuki
, p. 549 - 565 (2019/08/01)
Synthetic studies on palmarumycin C6 with a naphthyl acetal at the C-3 position in 4,7-dihydroxy-1-indanone as a lower homologue of spirobisnaphthalenes are described herein. We investigated three approaches: 1) Nazarov cyclization of benzoylketene acetal, 2) intramolecular Friedel-Crafts acylation of naphtho[1,8-de]-1,3-dioxin-2-aryl-2-acetic acid chloride, and 3) double oxa-Michael addition of 1,8-dihydroxynaphthalene to 3-bromo-1-indenone. The last approach successfully afforded the natural product after the removal of acetates that serve as protecting groups for phenolic hydroxyls under acidic conditions.
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.
