99316-53-7Relevant academic research and scientific papers
Enantioselective Total Synthesis of (?)-Spiroxins A, C, and D
Chen, Chong-Chong,Hu, Xiangdong,Shu, Xin,Yang, Jiayi,Yu, Tao
supporting information, p. 18514 - 18518 (2021/07/20)
Spiroxins A, C, and D are metabolites that have been identified in the marine fungal strain LL-37H248. Their unique polycyclic structures and intriguing biological activities make them attractive targets for the synthetic community. Based on a scalable en
Stereochemical Dichotomy in Two Competing Cascade Processes: Total Syntheses of Both Enantiomers of Spiroxin A
Ando, Yoshio,Tanaka, Daisuke,Sasaki, Ryota,Ohmori, Ken,Suzuki, Keisuke
supporting information, p. 12507 - 12513 (2019/08/16)
The first total synthesis of the marine antibiotic spiroxin A has been achieved for both enantiomeric forms. The discovery of two competing cascade processes triggered by two orthogonal stimuli, photo-irradiation or acid/base treatment, enabled the divergent conversion of a single chiral, nonracemic bis-quinone into both enantiomers of an advanced intermediate en route to both (?)- and (+)-spiroxin A. The mechanism of the enantiodivergence is discussed.
Synthesis of a 2-deoxyglucosyl analogue of medermycin
Brimble,Brenstrum
, p. 1624 - 1634 (2007/10/03)
The synthesis of a 2-deoxyglucosyl analogue 6 of the C-glycosylpyranonaphthoquinone antibiotic medermycin 1 is described. The key 3-acetyl-6-(2-deoxyglucosyl)-1,4-naphthoquinone 7 is prepared from 6-(2-deoxyglucosyl)-1,4-naphthoquinone 21, which in turn is available by C-glycosylation of naphthol 18 with glycosyl donor 12 using BF3·Et2O in acetonitrile followed by oxidative demethylation of the derived methyl ether 20. An acetyl group is then introduced at C-3 on naphthoquinone 21 by reductive monomethylation to naphthol 22, ortho bromination to bromide 24, methylation to 9, followed by Stille coupling with α-ethoxyvinyltributyltin (and hydrolysis) to afford the 3-acetylnaphthalene 8. Addition of 2-(trimethylsilyloxy)furan 13 to naphthoquinone 7, formed from oxidative demethylation of the naphthalene 8, affords the furofuran adducts 25 and 26 as an inseparable mixture of diastereomers. Oxidative rearrangement of this diastereomeric mixture using cerium (IV) ammonium nitrate affords the unstable diastereomeric lactols 27 and 28 also as a 1:1 inseparable mixture. Reduction of these lactols 27 and 28 with triethylsilane and BF3·Et2O at - 10 °C affords ethers 29 and 30 as a 1:1 mixture. Finally, conversion of ethers 29 and 30 to a 1:1 diastereomeric mixture of medermycin analogues 6 and 31 is achieved by treatment with boron tribromide which effects removal of the methoxy group at C-7, the benzyl ethers on the 2-deoxyglucose residue, and epimerisation at C-5.
The synthesis of oxygenated naphthyl stannanes possessing ortho-methoxy substituents for use in stille coupling reactions
Brimble, Margaret A.,Duncalf, Letecia J.
, p. 19 - 29 (2007/10/03)
The preparation of oxygenated naphthyl stannanes bearing an ortho-methoxy substituent is described, including stannanes (23) and (25) which are key intermediates for the synthesis of dimeric pyranonaphthoquinone antibiotics. Stannanes (17), (19) and (21)-(23) were obtained by metalhalogen exchange of the corresponding bromonaphthalenes. In an alternative approach to effect stannylation, a palladium(0)-mediated coupling reaction using hexaalkylditin reagents was examined. The Stille coupling reaction between naphthyl stannanes (23) and (25) and the corresponding bromonaphthalenes (11) and (24) failed to effect coupling to the desired binaphthyls.
Anodic Oxidation as a Synthetic Expedient to Naphthoquinone and Anthraquinone Ketals
Yang, Zhen,Cui, Yu Xin,Wong, Henry N. C.,Wang, Ru Ji,Mak, Thomas C. W.,et al.
, p. 3293 - 3302 (2007/10/02)
Some naphthoquinone and anthraquinone ketals have been prepared by anodic oxidation.Regioselective hydrolysis of the above diketals into monoketals is also described.Diels-Alder reaction of (E)-1-methoxybuta-1,3-diene with the monoketal of 1,4-dihydro-4,4-dimethoxy-5-benzyloxynaphthalene proceeded in a regioselective manner. Key words: naphthoquinone ketals, anthraquinone ketals, regioselective hydrolysis, Diels-Alder reaction.
Dimeric Naphthoquinones, XV. Syntheses of Diomelquinone A and its Dimer, 7,7'-Dihydroxy-8,8'-dimethoxy-3,3'-dimethyl-2,2'-bi-1,4-naphthoquinone
Laatsch, Hartmut
, p. 1847 - 1865 (2007/10/02)
Diomelquinone A (3b) and its dimer 3a are synthesized starting from 8-chloroplumbagin (4a) or juglone (2a); the ortho-quinones 7a and 11a are intermediates.
