- Lewis Acid-Catalyzed Stereoselective α-Addition of Chiral Aldehydes to Cyclic Dienol Silanes: Aqueous Synthesis of Chiral Butenolides
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The stereoselective α-addition to cyclic dienol silanes has rarely been exploited, in contrast to the well-studied γ-addition of conjugated butenolides. In this study, an unprecedent catalytic Mukaiyama aldol α-addition of 2-trimetylsiloxy furan to optically pure aldehydes in water-containing solvents is reported. The synthetic utility of this concept was demonstrated in the efficient synthesis of six bioactive natural products: vitexolide D, curcucomosin C, villosin, chinensine C, (+)-coronarin E and (E)-labda-7,11,13-trien-16,15-olid.
- Adamkiewicz, Anna,W?glarz, Izabela,Butkiewicz, Aleksandra,Woyciechowska, Marta,Mlynarski, Jacek
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p. 667 - 678
(2019/12/24)
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- Concise syntheses of coronarin A, coronarin E, austrochaparol and pacovatinin A
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Total syntheses of (+)-coronarin A (1), (+)-coronarin E (2), (+)-austrochaparol (3) and (+)-pacovatinin A (4) were achieved from the synthetic (+)-albicanyl acetate (6). Dess-Martin oxidation of (+)-albicanol (5) derived from the chemoenzymatic product (6) gave an aldehyde (7), which was subjected to Julia one-pot olefination using β-furylmethyl-heteroaromatic sulfones (8 or 9 ) gave (+)-trans coronarin E (2) and (+)-cis coronarin E (12) with high cis-selectivity. The synthesis of (+)-coronarin A (1) from (+)-trans coronarin E (2) was achieved, while (+)-cis coronarin E (12) was converted to the natural products (+)-(5S,9S,10S)-15,16-epoxy-8(17),13(16),14-labdatriene (13) and (+)-austrochaparol (3). By the asymmetric synthesis of (+)-3, the absolute structure of (+)-3 was determined to be 5S, 7R, 9R, 10S configurations. Homologation of (+)-albicanol (5) followed by allylic oxidation gave (7α)-hydroxy nitrile (17), which was finally converted to the natural (+)-pacovatinin A (4) in 8 steps from (+)-albicanol (5).
- Miyake, Takahiro,Uda, Keisuke,Kinoshita, Masako,Fujii, Mikio,Akita, Hiroyuki
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p. 398 - 403
(2008/12/23)
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- Synthesis of chinensines A-E
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(Chemical Equation Presented) Short and efficient syntheses of coronarin E (4) and chinensines A-E (5-9) have been accomplished. The use of two different types of reaction of singlet oxygen (1O2) lies at the heart of the synthetic st
- Margaros, Ioannis,Vassilikogiannakis, Georgios
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p. 4826 - 4831
(2008/02/05)
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- Synthesis of the marine furanoditerpene (-)-marginatone
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A synthesis of the marine labdane furanoditerpene (-)-marginatone 1 has been accomplished by a short sequence of reactions starting from (+)-coronarin E 5. The key step is the stereocontrolled-intramolecular electrophilic cyclisation of the (+)-dihydrocoronarin E 6, to the tetracyclic marginatane skeleton 7, which is subsequently functionalized by allylic oxidation to give 1. As (+)-coronarin E 5 was previously synthesized from (-)-sclareol 10, the herein reported preparation constitutes the first formal total synthesis of (-)-marginatone 1, by which its absolute configuration has been confirmed.
- Kolympadi, Maria,Liapis, Maria,Ragoussis, Valentine
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p. 2003 - 2010
(2007/10/03)
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- Facile Access to Optically Active Labdane-Type Diterpenes from (+)-Manool. Synthesis of (+)-Coronarin E, (+)-15,16-Epoxy-8(17),13(16),14-labdatriene, and (+)-Labda-8(17),13(Z)-diene-15,16-diol
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An efficient method for the synthesis of (+)-coronarin E (1), (+)-15,16-epoxy-8(17),13(16),14-labdatriene (2), and (+)-labda-8(17),13(Z)-diene-15,16-diol (3) from (+)-manool is described.
- Villamizar, Jose,Fuentes, Juan,Salazar, Franklin,Tropper, Eleonora,Alonso, Randolph
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p. 1623 - 1627
(2007/10/03)
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- Synthesis of (+)-coronarin E, (-)-7-epi-coronarin A and (+)-15, 16-epoxy-8(17), 13(16), 14-labdatriene from (+)-manool
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An efficient method for the synthesis of (+)-coronarin E 1, (+)-epi-coronarin A 2 and (+)-15, 16-epoxy-8(17), 13(16), 14-labdatriene 3 via the homodrimane 9, obtained in four steps from (+)-manool 5, is described.
- Villamizar, Jose,Salazar, Franklin,Fuentes, Juan,Tropper, Eleonora,Alonso, Randolph
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p. 504 - 506
(2007/10/03)
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- A concise synthesis and in vitro cytotoxicity of new labdane diterpenes
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A new series of labdane-related diterpenes have been synthesized from (- )-sclareoi and assayed in vitro cytotoxicity against mouse and human cancer cells. A key intermediate, homodrimane and furanolabdane derivatives show good in vitro cytotoxicity comparable to those of mitomycin C and adriamycin.
- Jung, Mankil,Ko, Imju,Lee, Seokjoon,Choi, Sun Ju,Youn, Byoung Hee,Kim, Soo Kie
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p. 3295 - 3298
(2007/10/03)
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- A concise conversion of (-)-sclareol into (+)-coronarin E and (-)-7- epi-coronarin A
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The first synthesis of natural (+)-coronarin E (1) and (-)-7-epi- coronarin A (8) was achieved from (-)-sclareol in four and five steps, respectively.
- Jung, Mankil,Ko, Imju,Lee, Seokjoon
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p. 1394 - 1396
(2007/10/03)
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- Synthesis of (+)-coronarin E
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The labdane-type diterpenoid (+)-coronatin E (5) has been synthesized in 7 steps from (-)-sclareol (1) for the first time.
- Mueller, Martin,Schroeder, Joerg,Magg, Christine,Seifert, Karlheinz
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p. 4655 - 4656
(2007/10/03)
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