10430-85-0Relevant articles and documents
Synthesis of Functionalized Aryloxy 1,3-Butadienes and Their Transformation to Diaryl Ethers via Diels-Alder Cycloaddition Reactions
Olsen, Richard K.,Feng, Xianqi,Campbell, Magnus,Shao, Rui-lian,Math, Shivanand K.
, p. 6025 - 6031 (2007/10/03)
The Diels-Alder reaction involving cycloaddition of aryloxy-substituted 1,3-butadienes with appropriate acetylenic electrophiles, followed by aromatization of the newly formed cyclohexadiene ring, has been used for the synthesis of diaryl ethers.The functionalized aryloxy 1,3-butadienes employed in this study were prepared by either of two methods: (1) methylenation of aryl esters via the Tebbe or related reagents, and (2) from 1-(aryloxy)-2-propanone by a sequence of formylation or alkylthio methylenation, and subsequent enolsilylation.A tetrasubstituted butadiene containing two phenoxy groups at the 1 and 3 positions also was prepared by the latter method.The cycloaddition reactions of 2,3-dioxy-substituted dienes occurred in high yield, but, as expected, with no regioselectivity to furnish nearly equal mixtures of regioisomeric cycloadducts.In contrast, application of 1,2,3-trihetero-substituted dienes resulted in regiospecific cycloaddition reactions.Transformation of the cyclohexadiene cycloadducts to an aromatic ring was accomplished by dehydrogenation with DDQ or by elimination during the cycloaddition process of a molecule of an alkyl mercaptan.A chiral acetylenic ketone derived from D- or L-serine underwent condensation, without racemization, with aryloxy dienes to provide diaryl ethers related to the isodityrosine antibiotics.
Electrochemical generation and reactions of acyloxytriphenylphosphonium ions
Ohmori, Hidenobu,Maeda, Hatsuo,Kikuoka, Masayuki,Maki, Toshihide,Masui, Masaichiro
, p. 767 - 776 (2007/10/02)
Constant-current electrolysis, in an undivided cell, of Ph3P in the presence of a carboxylic acid in CH2Cl2 containing 2,6-lutidinium perchlorate as the supporting electrolyte was shown to generate the corresponding acyloxyphosphonium ion, Ph3P+-OCOR, which was converted in situ to esters, amides, and β-lactams under mild conditions.
Pyranonaphthoquinone Antibiotics. Part 1. Syntheses of 9-Demethoxyeleutherins and 9-Deoxynanaomycin A Methyl Ester.
Kometani, Tadashi,Yoshii, Eiichi
, p. 1191 - 1196 (2007/10/02)
The syntheses of 9-demethoxyeleutherins and 9-deoxynanaomycin A methyl ester starting from indan-1-one derivatives are described.Lemieux-Johnson oxidation of the indene (15) derived from 4,7-dimethoxy-2-methylindan-1-one (14) afforded the diketone (16).The diol (17) obtained by lithium aluminium hydride reduction of (16) was treated with hydrochloric acid to give a ca. 1:2 mixture of cis-5,8-dimethoxy-1,3-dimethylisochroman (18) and the trans-isomer (19).Treatment of (16) with hydrogen bromide in acetic acid followed by catalytic reduction gave exclusively the cis-isochroman (18).Oxidative demethylation of the isochromans (18) and (19) afforded the quinones (22) and (23), benzannelation of which in two steps yielded 9-demethoxyeleutherin (24) and 9-demethoxyisoeleutherin (25) respectively.The same oxidation of the indene (32) derived from 4,7-dimethoxyindan-1-one (28) afforded the keto-aldehyde (33), which was treated with methoxycarbonylmethylenetriphenylphosphorane to give the conjugated ester (34).Reductive cyclisation of (34) with sodium borohydride afforded a ca. 1:3.5 mixture of cis-5,8-dimethoxy-3-methoxycarbonylmethyl-1-methylisochroman (35) and the trans-isomer (36).Oxidative demethylation of (36) followed by benzannelation produced 9-deoxynanaomycin A methyl ester (39).
