共查询到20条相似文献,搜索用时 15 毫秒
1.
(+)-Preussin (1) and its 5-epimer were synthesized from the divmylcarbmol (3) with Sharpless asymmetric epoxidation of 3 and the oxidative cyclization of 9 with PDC as the key steps 相似文献
2.
[structure: see text]. The total synthesis of cystothiazole A is described. Key steps of the synthesis include an Evans asymmetric catalytic aldol reaction, which established the required C4-C5 stereochemistry. The [2,4']-bis(thiazole) was obtained applying our methodology of electrophilic activation of amide. Semistabilized Wittig reaction between the phosphonium salt 3 and the aldehyde 2 afforded 1 in nine linear steps and 38% overall yield. 相似文献
3.
Xiaoyu Li Xiaozhen JiaoXiaoyu Liu Chengsen TianLiang Dong Yangyang YaoPing Xie 《Tetrahedron letters》2014
A practical total synthesis of the natural products (+)-isogalbulin and (+)-galbulin has been achieved in 10 steps from readily available 3-(3,4-dimethoxyphenyl)propanoic acid. The total yields were 12.3% and 12.9%, respectively. The key steps involved Evans asymmetric alkylation, Sharpless asymmetric epoxidation, and a highly regioselective opening of 1-benzyloxy-2,3-epoxides with an organoaluminum ate-complex formed by Me3Al and n-BuLi. 相似文献
4.
5.
V. Shekhar 《Tetrahedron letters》2010,51(6):946-31
A simple and highly efficient first total synthesis of cytotoxic (+)-crassalactone A starting from (R)-mandelic acid is described. The strategy involves the osmium tetroxide-catalyzed cis-hydroxylation and the stereoselective addition of ethyl lithiopropiolate to a chiral aldehyde intermediate as key steps. 相似文献
6.
Zhi-Xiang FengWei-Shan Zhou 《Tetrahedron letters》2003,44(3):497-498
A total synthesis of (+)-lentiginosine was achieved by using ethyl 3-(pyridin-2-yl)acrylate N-oxide as the starting material and an improved Sharpless asymmetric dihydroxylation as the key step. 相似文献
7.
Toshikazu SaitohToshio Suzuki Masashi SugimotoHisahiro Hagiwara Takashi Hoshi 《Tetrahedron letters》2003,44(15):3175-3178
The stereoselective total synthesis of (+)-laurallene is described. The required key oxocene skeleton possessing trans-orientated alkyl substituents at the α,α′-positions was stereoselectively constructed via the cyclization of the corresponding hydroxy epoxide promoted by Eu(fod)3. 相似文献
8.
9.
Divya Tripathi 《Tetrahedron letters》2008,49(49):7012-7014
A versatile and efficient method for the enantioselective synthesis of 2,7-cis-disubstituted oxepane 1c, (+)-isolaurepan, using oxidative resolution of a secondary alcohol and highly diastereoselective Et3SiH/TMSOTf-promoted reductive cyclization of a hydroxy ketone is described. 相似文献
10.
The first enantioselective total synthesis of (+)-sarcodictyenone is described [4.3% overall yield from (5R,6R)-6-methyl-5-trimethylsily-2-cyclohexenone]. This work establishes the absolute stereochemistry of the natural product. 相似文献
11.
Liang-Qun Li Ming-Ming Li Dong Chen Hao-Miao Liu Hui-chun Geng Jun Lin Hong-Bo Qin 《Tetrahedron letters》2014
Catalytic asymmetric formal total synthesis of (+)-dichroanone and (+)-taiwaniaquinone H has been achieved. Key step involved construction of all-carbon quaternary carbon by palladium-catalyzed conjugate addition of arylboronic acid to 3-methyl cyclohexenone. Furthermore, a new approach to build [6-5-6] tricyclic backbone via formyl introduction and subsequent aldol-type condensation was also explored. 相似文献
12.
Toshio Honda Hidenori Namiki Masayuki Watanabe Hirotake Mizutani 《Tetrahedron letters》2004,45(27):5211-5213
The first diastereoselective chiral synthesis of (+)-viroallosecurinine, isolated from Securinega virosa as a cytotoxic alkaloid, was achieved by using a chelation-controlled addition of an alkyne moiety to the corresponding ketone, and a ring-closing metathesis, as key reactions. 相似文献
13.
A convergent selective route to (+)-brefeldin A (BFA) and 7-epi-BFA was developed, with the crucial C-4/C-5 stereogenic centers were established using Crimmins asymmetric aldolization. 相似文献
14.
An expedient synthesis of quinolactacin A2 from N-methylisatoic anhydride and N-Boc-(2S,3S)-isoleucine has been achieved. The key step involves the Friedländer-type annulation of isatoic anhydride and β-ketoester derived from isoleucine. 相似文献
15.
Daisuke Matsumura 《Tetrahedron letters》2009,50(26):3356-2160
The total synthesis of natural (+)-spiculoic acid A, a new cytotoxic marine natural product of polyketide origin, has been accomplished for the first time. The key step of the total synthesis was a stereoselective and high-yielding intramolecular Diels-Alder reaction of a highly functionalized (E,E,E)-2,7,9-dodecanal derivative for the construction of the core tetrahydroindan-2-one skeleton. 相似文献
16.
(+)-1-Deoxy-6-epi-castanospermine was asymmetrically synthesized in ten steps from α-furfuryl amine derivative 6 in 2.9% overall yield. The kinetic resolution of α-furfuryl amine derivative 6 and Sharpless AD reaction of 14 were used as key steps. 相似文献
17.
An enantioselective total synthesis of the lindenane sesquiterpene (+)-sarcandralactone A has been accomplished for the first time. The synthesis features a SeO2-mediated [2,3]-sigmatropic rearrangement for the facile construction of the tertiary allylic alcohol as a single diastereoisomer. 相似文献
18.
A convergent and highly stereoselective formal total synthesis of the naturally occurring, cytotoxic 14-membered macrolide neopeltolide has been achieved via two Prins cyclizations. 相似文献
19.
A stereoselective formal total synthesis of (+)-hyperaspine via a tandem aza-Michael reaction as the key step in good yield is reported. 相似文献
20.
A novel and stereospecific approach to (+)-preussin that would permit the synthesis of analogs for structure activity relationship studies, is disclosed. The key step includes the regio- and stereoselective elaboration of a bromohydrin via intramolecular sulfinyl group participation. 相似文献