- Synthesis and bioactivity of erythro-nordihydroguaiaretic acid, threo-(-)-saururenin and their analogues
-
Full details of the total syntheses of erythro-nordihydroguaiaretic acid, threo-(-)-saururenin and their analogues are presented. The syntheses were based on a unified synthetic strategy involving the Stobbe reaction, alkylation to construct the skeleton
- Xia, Yamu,Zhang, Yuanyuan,Wang, Wei,Ding, Yining,He, Rui
-
p. 1325 - 1335
(2011/09/12)
-
- Oxidative Homocoupling of Chiral 3-Arylpropanoic Acid Derivatives. Application to Asymmetric Synthesis of Lignans
-
The oxidative homocouplings of lithium enolates of (4S)-3-(3-arylpropanoyl)-4-isopropyl-2-oxazolidinones and (4R,5S)-1-(3-arylpropanoyl)-3,4-dimethyl-5-phenyl-2-imidazolidinones gave the corresponding R,R-dimers stereoselectively with TiCl4, Ph
- Kise, Naoki,Ueda, Takako,Kumada, Kimikage,Terao, Yuichi,Ueda, Nasuo
-
p. 464 - 468
(2007/10/03)
-
- Enantiocontrolled Synthesis of Burseran, Brassilignan, Dehydroxycubebin, and Other Tetrahydrofuran Lignans in Both Enantiomeric Forms. Application of Intermolecular Nitrile Oxide Cycloadditions and Lipase Mediated Kinetic Resolutions
-
Several natural and unnatural tetrahydrofuran lignans have been synthesized by a convergent approach.Our methodology utilizes a nitrile oxide cycloaddition to dihydrofuran 8 and an enzymatic resolution of alcohols 11 by lipase PS.The lipase-mediated kinetic resolution of alcohols 11 furnished both enantiomers of the lignan precursors 12 and 14 in high optical purity (>99percent ee).This is followed by a SN2 displacement of tosylates 15 and 18 by α-lithiobenzyl phenyl sulfides.In this manner, both enantiomers of 3,4-dibenzyltetrahydrofuran (17a, 20a), 3,4-bis(3-methoxybenzyl)tetrahydrofuran (17b, 20b), brassilignan (17c, 20c), dehydroxy cubebin (17d, 20d), and burseran (17e, 20e) were synthesized in overall yields of 6-16percent.
- Gaboury, Janet A.,Sibi, Mukund P.
-
p. 2173 - 2180
(2007/10/02)
-
- General Conjugate-Addition Method for the Synthesis of Enantiomerically Pure Lignans. Total Synthesis of (-)- and (+)-Burseran, (-)-Dehydroxycubebin, (-)-Trichostin, (-)-Cubebin, (-)-5''-Methoxyhinokinin, and (-)-Hinokinin
-
Conjugate addition of benzylic diphenyldithioacetal anions to enantiomerically pure (-)-(2R)-and (+)-(2S)-(benzyloxy)-2,5-dihydro-4-furan (2 r and 2 s) gave complete lignan skeletons of the dibenzylbutane class.Desulfurization followed by hydrogenolysis and, when appropriate, oxidation gave the title enantiomerically pure > 99 percent ee) lignans 45 - 50 in 24 - 35 percent overall yields from 2 r and 2 s.
- Rehnberg, Nicola,Magnusson, Goeran
-
p. 4340 - 4349
(2007/10/02)
-
- LIGNANDS FROM NECTANDRA TURBACENSIS
-
Bark and wood of Nectanandra turbacensis (Lauraceae) contain, besides the known furofuran lignands (+)-sesamin, (+)-demethoxyexcelsin and (+)-piperitol, the novel (1R,5R,2S,6S)-2-(3'-methoxy-4',5'-methylenedioxyphenyl)-6-(4"-hydroxy-3"-methoxyphenyl)-3,7-dioxabicyclooctane and (1R,2S,5R)-2-(3'-methoxy-4',5'-methylenedioxyphenyl)-3,7-dioxa-6-oxobicyclooctane. Key Word Index--Nectandra turbacensis; Lauraceae; furofuran lignands; 2-aryl-3,7-dioxa-6-oxobicyclooctane
- Carvalho, Mario G. De,Yoshida, Massayoshi,Gottlieb, Otto R.,Gottlieb Hugo E.
-
p. 265 - 268
(2007/10/02)
-
- NEM LIGNANS FROM THE HEARTWOOD OF CLEISTANTHUS COLLINUS
-
The isolation and characterisation of five new compounds and nine known compounds from the heartwood of Cleistanthus collinus are reported.The new compounds are wodeshiol 16, 3,4-dihydrotaiwanin C 20, and three new glycosides 24, 25 and 26 of diphyllin and taiwanin E.The 1H and 13C NMR spectra of these compounds are also reported.
- Anjaneyulu, A. S. R.,Ramaiah, P. Atchuta,Row, L. Ramachandra,Venkateswarlu, R.,Pelter, A.,Ward, R. S.
-
p. 3641 - 3652
(2007/10/02)
-