共查询到20条相似文献,搜索用时 31 毫秒
1.
Paulo H.S. PaiotiFernando Coelho 《Tetrahedron letters》2011,52(46):6180-6184
We disclosed herein a diastereoselective approach for the total syntheses of (±)-Leiocarpin A and (±)-Goniodiol. These biologically active styryl lactones were obtained from a common intermediate, prepared in five steps and 40% overall yield, using a simple synthetic sequence starting from a Morita-Baylis-Hillman adduct. The total syntheses of these styryl lactones were accomplished in nine steps. This is the first report on the total synthesis of this class of natural products starting from Morita-Baylis-Hillman adduct. 相似文献
2.
Qing Ri Li Seung In KimSook Jin Park Hye Ran YangA Reum Baek In Su KimYoung Hoon Jung 《Tetrahedron》2013
The total synthesis of (+)-valienamine and (−)-1-epi-valienamine was concisely accomplished from readily available d-glucose via a highly diastereoselective amination of chiral benzylic ether using chlorosulfonyl isocyanate, intramolecular olefin metathesis, and diastereoselective reduction of cyclic enone using l-Selectride as the key steps. 相似文献
3.
《Tetrahedron: Asymmetry》2000,11(23):4681-4686
A short and efficient synthesis of the title compounds is described. (S)-(−)-β-Cuparenone was prepared in 31% yield from p-tolualdehyde and mesityl oxide in eight steps. Absolute stereochemistry was established by means of a diastereoselective cyclopropanation using (R,R)-hydrobenzoin as a recoverable auxiliary. 相似文献
4.
The bicyclic core of octosyl acid A has been prepared using a diastereoselective acetylide addition and 6-endo selenoetherification as key steps. A detailed study of the selenoetherification reaction and difficulties encountered in the conversion of a phenyl group to a carboxylic acid will be discussed. 相似文献
5.
Liyanage W Weerasinghe L Strong RK Del Valle JR 《The Journal of organic chemistry》2008,73(18):7420-7423
Two configurationally stable carbon-based analogues of pyochelin have been prepared from Boc-pyroglutamic acid-tert-butyl ester in 11 and 13 steps. Introduction of the amino group was achieved by a highly diastereoselective electrophilic azidation reaction to afford novel bis-alpha-amino acid proline derivatives. 相似文献
6.
Several fluorinated 1,3-diaminocyclopentanes, previously reported to be useful RNA structural probes, can be prepared in a diastereoselective manner from a single bicyclic hydrazine precursor, in 3 to 9 steps. 相似文献
7.
[reaction: see text] The N7-C25 fragment of the potent and selective cytotoxic agent psymberin has been prepared through a short (12 linear steps, 15 total steps) and stereoselective sequence. Highlights of this route include a very rapid construction of the pentasubstituted arene, a substrate-controlled diastereoselective fragment coupling using a Mukaiyama aldol reaction, and an efficient entry into a key tetrahydropyranyl cyanide. 相似文献
8.
Qian X Zheng B Burke B Saindane MT Kronenthal DR 《The Journal of organic chemistry》2002,67(11):3595-3600
A highly stereoselective synthesis of the novel tryptase inhibitor BMS-262084 was developed. Key to this synthesis was the discovery and development of a highly diastereoselective demethoxycarbonylation of diester 12 to form the trans-azetidinone 13. BMS-262084 was prepared in 10 steps from D-ornithine in 30% overall yield. 相似文献
9.
A concise and scalable synthesis of high enantiopurity (-)-D-erythro-sphingosine using peptidyl thiol ester-boronic acid cross-coupling 总被引:1,自引:0,他引:1
A short and efficient synthesis of high enantiopurity (-)-D-erythro-sphingosine has been achieved in 71% yield over 6 steps from N-Boc-L-serine. The key steps are high yield, racemization-free, palladium-catalyzed, copper(I)-mediated coupling of the thiophenyl ester of N-Boc-O-TBS L-serine with E-1-pentadecenyl boronic acid and the highly diastereoselective reduction of the resulting peptidyl ketone with LiAl(O-t-Bu)3H. By using this concise route (-)-D-erythro-sphingosine can be prepared on large scale and in high enantio- and diastereopurity (ee >99%, de up to 99%). 相似文献
10.
Kenshu Fujiwara Yu-ichi Aki Fuyuki Yamamoto Mariko Kawamura Masanori Kobayashi Azusa Okano Daisuke Awakura Shunsuke Shiga Akio Murai Hidetoshi Kawai Takanori Suzuki 《Tetrahedron letters》2007,48(26):4523-4527
In this study, we synthesized the C8-C20 and C21-C30 segments of the diarrhetic shellfish toxin pectenotoxin 2. The C8-C20 segment was assembled from a phosphonate corresponding to the C8-C15 segment (prepared from l-malic acid in 19 steps) and an aldehyde corresponding to the C16-C20 segment (synthesized from 3-methyl-3-butenol in nine steps) by a twelve-step process including the Horner-Wadsworth-Emmons reaction, regio- and stereoselective reduction of the resulting enone, diastereoselective epoxidation, and 5-exo epoxide cleavage forming the C-ring. The C21-C30 segment was constructed in 13 steps from (S)-glycidol via a route involving E-ring formation by 5-exo epoxide cleavage and stereoselective methylation at C27 by the Evans method. 相似文献
11.
The reaction of glycidic amides with various functionalized nitriles to afford norstatine analogs in a regio- and diastereoselective fashion (43-99% yield) is described. Utilizing this chemistry, a 20 membered solution phase library was prepared in two steps featuring three points of diversity. 相似文献
12.
The first total synthesis of the novel glycosylated tetrahydroisoquinoline antitumor antibiotic (-)-lemonomycin has been accomplished (15 steps from 9). The highly convergent synthesis relies on a key asymmetric dipolar cycloaddition to set the stereochemistry of the aglycone core, a Suzuki fragment coupling to connect the diazabicycle to the aryl subunit, and a stereoselective Pictet-Spengler reaction that incorporates the aminoglycoside subunit directly into the core structure without the need for late-stage glycosylation or protecting group manipulations. The novel aminoglycoside was prepared using a highly diastereoselective Felkin-controlled acetate aldol addition reaction to a threonine-derived ketone. 相似文献
13.
An enantioselective formal total synthesis of (−)-trachyspic acid was carried out using, as key steps, an asymmetric aldol reaction of a chiral oxazolidinone and a diastereoselective alkylation of a chiral 1,3-dioxolan-2-one. The key lactone 3 was synthesized in five steps starting from dioxolanone 9. 相似文献
14.
The diastereoselective synthesis of (±)-trans-transoid-7-bromo-8-hydroxy-1-methyl-1,2,3,4,4a,5,10,10a-octahydro-10-phenylbenzo[g]quinoline ( 8 ) is described, using an intramolecular Diels-Alder reaction and a reductive cyclisation for piperidine ring-formation as key steps. Compound 8 was prepared as a putative D-1 receptor antagonist which contains (2,2-diphenylethyl)amine as a partial structure. 相似文献
15.
The synthesis of arylated dihydropyrans and unsaturated lactones starting from enantiomerically pure alpha-hydroxy ketones (prepared by an enzyme-catalyzed benzoin condensation) is described. The key steps are a highly diastereoselective addition of vinyl metal compounds under chelate control and a ruthenium-catalyzed ring-closing olefin metathesis reaction. Elucidation of the relative configuration of the final products was achieved by NOE experiments. 相似文献
16.
(+/-)-Deoxydysibetaine 2 and 4-epi-dysibetaine 3 were prepared in a few steps from methyl pyroglutamate through a regioselective Mannich reaction at C-2. Natural (2S,4S)-dysibetaine 1, a sponge metabolite isolated from Dysidea herbacea, and (2S)-2 were synthesized from enantiopure (S)-pyroglutaminol with very high stereoselectivity. The key steps were an original formation of stereogenic quaternary center C-2 and the diastereoselective hydroxylation at C-4. 相似文献
17.
An orthogonally protected derivative 1 of (2R,3R,4S)-4,7-diamino-2,3-dihydroxyheptanoic acid, the unusual amino acid residue of the biologically active marine peptides such as callipeltins A and D and neamphamide A, was efficiently prepared in 10 steps and 30% overall yield from a commercially available L-ornithine derivative 2. The key step includes the N-diphenylmethylene-controlled diastereoselective dihydroxylation of (Z)-ester 3 with >13:1 selectivity for the desired isomer. 相似文献
18.
Naïma Khiri 《Tetrahedron letters》2005,46(35):5807-5810
Enantiomerically pure (E)-β-sulfinylenones are smoothly prepared from β-ketoesters in three steps with good overall yield. Since they can be the substrates of many diastereoselective reactions, they represent versatile precursors of a wide range of chiral building blocks. We propose a rationale to explain the formation of (E)-β-sulfinylenones from the corresponding δ-enol-methylethers. 相似文献
19.
A concise and highly diastereoselective synthesis of (+)-astropaquinone B and (+)-astropaquinone C is reported. The synthetic strategy is based on an efficient combination of Dötz benzannulation using a chiral alkyne to construct the naphthalene unit and a highly diastereoselective oxa-Pictet-Spengler reaction to install the trans-configured pyran ring as the key steps. 相似文献
20.
A highly diastereoselective and enantioselective synthesis of the decahydro-as-indacene nucleus 12 of (-)-spinosyn A (1) is reported. By implementing the steric directing group strategy, tricyclic lactone 37 was produced from a remarkably diastereoselective transannular Diels-Alder reaction of lactone 9. The tricyclic core of the natural product was then obtained by using an Ireland-Claisen ring contraction of 37. Reversal of the order of these two steps resulted in an almost complete loss of diastereoselectivity. 相似文献