共查询到20条相似文献,搜索用时 15 毫秒
1.
Sequential Baylis-Hillman/ring-closing metathesis (RCM) approach toward the total synthesis of (+)-MK7607 and (+)-streptol starting from (R,R)-tartaric acid is reported. 相似文献
2.
A first total synthetic route has been reported for the synthesis of Phomolide G and H. The syntheses of fragments were initiated from commercially available and inexpensive starting material (R)-epichlorohydrin. The synthesis involves a key Sharpless epoxidation, stereoselective epoxide opening, lactonization and ring closing metathesis (RCM). 相似文献
3.
An efficient and convenient strategy for the enantioselective synthesis of enantiomerically enriched umbelactones is described utilizing a lipase-mediated resolution protocol, Baylis-Hillman reaction and ring closing metathesis as key steps. The lipase-resolution is carried out using several lipases from various sources in different solvents to afford the required intermediate 8 in good yield and high enantioselectivity. 相似文献
4.
Saravanan Gowrisankar 《Tetrahedron》2006,62(17):4052-4058
Construction of furo[3,4-c]pyran ring skeleton was achieved starting from the Baylis-Hillman adducts. The synthesis was carried out by the successive introduction of propargyl alcohol, radical cyclization, reduction, allylation, and finally ring-closing metathesis reaction. 相似文献
5.
Debendra K. Mohapatra Dhondi K. Ramesh Mukund S. Chorghade Robert H. Grubbs 《Tetrahedron letters》2007,48(14):2621-2625
The first synthesis of a newly found naturally occurring anti-malarial nonenolide is described. A pivotal step in the synthesis is the ring-closing metathesis of a dienoic ester prepared by coupling an acid and alcohol that were stereoselectively synthesized from (S)-α-hydroxy-γ-butyrolactone and 1,2-O-isopropylidene d-glyceraldehyde, respectively. 相似文献
6.
We have developed an efficient method for the synthesis of 2,5-dihydrofuran and 2,5-dihydropyrrole skeletons from the simply modified Baylis-Hillman adducts via RCM reaction. 相似文献
7.
The first stereoselective total synthesis of trichodermone A using Baylis-Hillman and ring-closing metathesis (RCM) reactions as key steps is reported. 相似文献
8.
It has been demonstrated that an aryl-β-C-glycoside can be efficiently constructed via a sequence consisting of Brown asymmetric allylation, ring-closing metathesis, hydrogenation, nucleophilic addition, and stereoselective Et3SiH reduction. The antibiotic natural product (−)-centrolobine was synthesized in this manner utilizing only five steps with an overall 53% yield. 相似文献
9.
In this communication we report a stereoselective total synthesis of N-Boc-dolaproine (Dap), an amino acid residue of the antineoplastic pentapeptide Dolastatin 10. Our strategy is based on a Baylis-Hillman reaction between N-Boc-prolinal and methyl acrylate, followed by a diastereoselective double bond hydrogenation and hydrolysis of the ester function. 相似文献
10.
Jeong Mi Kim 《Tetrahedron letters》2009,50(15):1734-5609
An expedient protocol of aralkylation of Baylis-Hillman adducts has been developed. This method used Pd-catalyzed decarboxylative protonation strategy to the allyl ester precursor that was made from the Baylis-Hillman adduct and allyl phenylacetate. 相似文献
11.
We synthesized novel tetracyclic fused indole derivatives via the intramolecular Heck reaction of indole-containing Baylis-Hillman adducts in good to moderate yields. 相似文献
12.
Ko Hoon Kim 《Tetrahedron letters》2009,50(38):5322-5609
We disclosed an efficient synthetic method of 2,4,5-trisubstituted 1,4-pentadienes from Baylis-Hillman adducts via the Pd-catalyzed decarboxylation-elimination protocol as the key step. 相似文献
13.
Novel pentacyclic benzoazepino[2,1-a]isoindole derivatives were synthesized by palladium-mediated consecutive cyclization from enamides of Baylis-Hillman adducts. 相似文献
14.
Akio Kamimura Rie MoritaKenji Matsuura Hiromasa MitsuderaMasashi Shirai 《Tetrahedron》2003,59(50):9931-9938
A convenient stereoselective synthesis of β-lactams from thio-Michael/aldol tandem adduct is described. syn-Selective tandem reaction followed by amidation and intramolecular SN2 reaction provided β-lactams in diastereomerically pure form. The tandem reaction with aliphatic aldehydes, on the other hand, afforded a mixture of diastereomers of corresponding tandem adducts in about 3:1 ratio so that the conversion to β-lactams afforded a diastereomeric mixture. As an alternative approach to prepare the tandem adducts, the stereoselective Michael addition of aliphatic thiols to Baylis-Hillman adduct was developed. The stereoselectivity was sensitive to the protective group at the hydroxyl group and TBS protection brought the most successful syn-selective formation of the tandem adducts. The procedure could be applied to the ketone derivatives of the Baylis-Hillman adduct but no selectivity was observed for the nitrile-Baylis-Hillman adducts. A similar conversion of the adduct provided desired β-lactams stereoselectively. 相似文献
15.
16.
Toshimi Anzo 《Tetrahedron letters》2007,48(48):8442-8448
A formal synthesis of the antimicrobial tricyclic macrolides, tubelactomicins A and E, featured by a transannular Diels-Alder (TADA) approach, has been explored. The key issue for the transannular cyclization was the synthesis of a 24-membered macrolactone equipped with all the requisite functionalities, which has been achieved using an intramolecular Hiyama cross-coupling strategy. The Hiyama coupling reaction spontaneously triggered off the TADA reaction. From the endo-TADA adduct, formal syntheses of tubelactomicins A and E were achieved. The 24-membered macrolactone formation was also achieved via an intramolecular ring-closing metathesis approach. 相似文献
17.
During the radical cyclization of enamide derivatives 4 we found unusual formation of dihydropyrido[2,1-a]isoindolone derivatives 5. The enamides were synthesized in four steps from the Baylis-Hillman adducts of ortho-bromobenzaldehydes. 相似文献
18.
Mi Jung Lee 《Tetrahedron》2006,62(13):3128-3136
A new and regioselective [4+2] benzannulation protocol toward polysubstituted benzenes was developed. A nitroalkane derivative, which was prepared from Baylis-Hillman adduct, served as the four-carbon unit and a Michael acceptor as a two-carbon unit. Vinyltriphenylphosphonium salt could also be used as a Michael acceptor efficiently. 相似文献
19.
A palladium-mediated carbonylative cyclization reaction of Baylis-Hillman adducts is disclosed. This simple, efficient and straightforward sequence leads to the formation of an array of 3-alkenylphthalides with different substitution patterns on the aromatic ring, with good chemical yields and selectivities. 相似文献
20.
Stephen G. Davies Ai M. Fletcher Paul M. Roberts Andrew D. Smith 《Tetrahedron》2009,65(49):10192-1121
Conjugate addition of lithium (R)-N-allyl-N-(α-methylbenzyl)amide or lithium (R)-N-but-3-enyl-N-(α-methylbenzyl)amide to an alkyl hexa-2,4-dienoate or alkyl hepta-2,6-dienoate, followed by ring-closing metathesis of the olefin functionalities within the resultant β-amino ester, generates a range of diastereoisomerically pure azacycles in good yield. These homochiral templates are readily transformed to a range of piperidine alkaloids of the Sedum family, and the corresponding five-, seven- and eight-membered ring homologues. 相似文献