Efficient Syntheses of 1-Arylnaphthalene Lignan Lactones and Related Compounds from Cyanohydrins
摘要:
1-Arylnaphthalene lignan lactones were synthesized in good yields from O-(tert-butyldimethylsilyl)cyanohydrins in two steps based on a conjugate addition-aldol reaction, followed by acid-catalyzed closure to form the naphthalene ring. 4-Hydroxy-1-arylnaphthalene lignan lactones were also synthesized by conjugate addition-aldol reaction, followed by aromatization-lactonization.
1-Arylnaphthalenelignans were synthesized in good yields from O-t-butyldimethylsilylcyanohydrins in two steps based on a newapproach involving a tandem conjugate addition-aldol reaction, followed by an acid-catalyzed construction of the naphthalene ring.
(±)-Isopodophyllotoxone and (±)-picropodophyllone were synthesized stereoselectively from the O-(t-butyldimethylsilyl) cyanohydrins (3a) in good yields. This new method was successfully applied to the syntheses of a variety of lignans of the aryltetralin series.
Stereoselective Syntheses of <i>Cis</i>- and <i>Trans</i>-Isomers of α-Hydroxy-α,β-dibenzyl-γ-butyrolactone Lignans: New Syntheses of (±)-Trachelogenin and (±)-Guayadequiol
Cis- and trans-isomers of alpha-hydroxy-alpha,beta-dibenzyI-gamma-butyrolactone lignans 1a,d-g and 2a,c,d were stereoselectively synthesized in good yields based on the electrophilic addition to the metal enolate of alpha-benzyl-gamma-butyolactone derivatives 1l-o and 3 as a key step, This method was applied to the syntheses of (+/-)-trachelogenin and (+/-)-guayadequiol, representative examples of the trans- and cis-isomers of alpha-hydroxy-alpha,beta-dibenzyl-y-butyrolactone lignan series.
Moritani, Yasunori; Ukita, Tatsuzo; Hiramatsu, Hajime, Journal of the Chemical Society. Perkin transactions I, 1996, # 22, p. 2747 - 2754
Enzyme-catalyzed Dediastereomerization of Dibenzylbutanolides by Plant Cell Cultures
作者:Masumi Takemoto、Yuki Matsuoka、Kiyoshi Tanaka、Kazuo Achiwa、Nikolay Stoynov、James Peter Kutney
DOI:10.3987/com-01-s(k)22
日期:——
We have been developed a novel biocatalytic dediastereornerization method, i. e., reactions allowing the transformation of two diastereorners into one diastereomer in quantitative yield. When a mixture of two diastereomers (4R*-5) and (4S*-5) (1:1 ratio) was subjected to Catharanthus roseus cells in B5 medium, dediastereornerization took place to give a single diastereomer (4R*-5) in 80 % chemical yield with 100 % diastereomeric excess and 0 % enantiomeric excess.