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1.
A novel approach to (±)-epipodophyllotoxin () and hence also (±)-podophyllotoxin () is described, involving as a key-step the stereoselective ring closure of the TMS-ester derived from to the tetralin derivative with mesyl chloride. 相似文献
2.
A new and convenient synthesis of 2-isopropylfuro-(2,3-b)quinolines () from 3-(3-methylbut-1-enyl)-2-quinolones () is described. A neat synthesis of the alkaloids (±)-lunacrine (), (±)-lunasine () and (±)-demethoxylunacrine () is also reported. 相似文献
3.
Takeshi Imanishi Noriyuki Yagi Hiroaki Shin Miyoji Hanaoka 《Tetrahedron letters》1981,22(40):4001-4004
A new synthesis of (±)-ibogamine () and (±)-epiibogamine (), involving the intramolecular Michael addition of the keto unsaturated ester (), is described. 相似文献
4.
New synthesis of Eucarvone , (±)-Nuciferal and (±)-Manicone are described from trimethylsilyl enol ethers , and via their chloromethylenation products by means of a two carbons homologation reaction. 相似文献
5.
The title intermediate () is produced on photolysis of hexakis(2,6-diethyl-phenyl)cyclotrigermane () or bis(2,6-diethylphenyl)bis(trimethylsilyl)germane () as evidenced by trapping experiments, and thermally dimerizes to tetrakis(2,6-diethyl-phenyl)digermene (). Diarylgermylenes such as do not form stable triethylamine adducts (e.g. ) as has been previously reported. 相似文献
6.
John T Lai 《Tetrahedron letters》1982,23(6):595-598
α-(-Butylamino)-isobutyramides () can be prepared from α-haloisobutyramides () and -butylamine with sodium hydroxide in Favorskii-like reactions. 相似文献
7.
The first and stereoselective total synthesis of (±)-tecomanine () has been achieved from ethyl 1,6-dihydro-3(2H)-pyridinone-1-carboxylate () as a synthon. 相似文献
8.
The reaction of Pt(PPh3)4 with CH2Cl1 in benzene yields the cationic ylide complex -[Pt(PPh3)2(CH2PPh3)Cl]I in high yield. This complex has been converted to -[(PPh3)2(CH2PPh3)X]X (X Br or I) by reaction with LiBr or NaI. Reaction of -[Pt(PPH3)I]I with iodine yields -[Pt(PPh3)2(CH2PPh3)I]I3. Nmr data are given in support of the suggested structures. 相似文献
9.
In the paper a highly stereoselestive route to -1,4-di-tert-butylbutatriene --BuCu induced 1,3-substitution in ()--BuCHC(Br)CCH is described. 相似文献
10.
(±)-Apovincamine () is synthesized by dehydration of the β-hydroxyrster () obtained by alkylation of the aldehyde () with metal chloroacetate 相似文献
11.
(±)-Isoagatholactone and (±)-12α-hydroxyspongia-13(16),14-dien , a fundamental skeleton of spongiadiol and its congeners, have been synthesized from (±)-labda-8(20),13-dien-15-oic acid . 相似文献
12.
A short, stereoselective synthesis of (±)-warburganal (), its C-9 epimer () and the related sesquiterpene dialdehyde (±)-isotadeonal is presented. 相似文献
13.
Starting from the aldehydes and the acetylene is prepared via the borane by means of a combined Wittig reaction-hydroboration reaction sequence. may be converted into the (E)-6,(Z)-11-hexadecadienylacetate () and the corresponding aldehyde . The synthetic route proceeds with high stereospecifity (isomeric purity of and ? 97%). 相似文献
14.
Treatment of octaethylporphyrin () or tetraphenylporphyrin () with more than two equiv of thallium(I) ethoxide gives the corresponding stable bis[thallium(I)] porphyrin complexes () and (), respectively; these thallium(I) porphyrins are shown to have very different chemical and spectroscopic properties than do the corresponding thallium(III) porphyrin complexes. 相似文献
15.
(±)-Lycodine () has been synthesized in five steps from cyanoenone . The approach has also been applied to a new synthesis of (±)-lycopodine (). Both alkaloids are available in better than 20% overall yield from enone . 相似文献
16.
G.R. Clark C.M. Cochrane W.R. Roper L.J. Wright 《Journal of organometallic chemistry》1980,199(2):C35-C38
The osmium carbyne complex, Os(CR)Cl(CO)(PPh3)2, (R p-tolyl) reacts with Group I halides to form the mixed dimetallocyclopropene species, R)Cl(CO)(PPh3)2, R)Cl(CO)(PPh3)2, R)Cl(CO)(PPh3)2, and [R)Cl(CO)(MeCN)(PPh3)2] ClO4 X-ray crystal structure determination of R)Cl(CO)(PPh3)2 confirms the presence of a three-membered ring and the structure can be viewed as the “acetylene-like” interaction of an osmium—carbon triple bond with AgCl. In acid solution AgCl is precipitated and an alkylidene complex results from proton addition to the carbyne ligand. 相似文献
17.
Gábor Blaskó Natesan Murugesan Alan J. Freyer Daniella J. Gula Bilge Şener Maurice Shamma 《Tetrahedron letters》1981,22(33):3139-3142
Stereoselective rearrangement of indenobenzazepine cis ketols and with TPAA in pyridine produces spirobenzylisoquinolines and , respectively. The latter product is also obtained by rearrangement of trans ketol . The transformation of ketols and must, therefore, proceed through the intermediacy of aziridinium cation . A similar process obtains in the transformation of to . NaBH4 reduction of gives (±)-raddeanine (). Rearrangement of diol supplies directly. (±)-Yenhusomine () is obtained from the reamangement of either diol, or . In like fashion, diols and supply spirobenzylisoquinoline . 相似文献
18.
The Functionalized Grignard reagent reacts with allylic chloride , in the presence of Li2CuCl4, to provide lactarol-THP ether which is subsequently converted to (±)-lactaral in 72% overall yield from . 相似文献
19.
Tatsuhiko Nakano A.C. Spinelli A. Martín A. Usubillaga Andrew T. McPhail Kay D. Onan 《Tetrahedron letters》1982,23(35):3627-3630
cleavage of the epoxide () of methyl (-)-kaur-9(11)-en-19-oate () with boron trifluoride-ether in benzene and in acetic anhydride yielded () and (), respectively. On epoxidation with -chloroperbenzoic acid in the presence of -nitrosomethyl urea, () suffered a backbone rearrangement to form (). 相似文献
20.
(±)-Sinularene () as well as (±)-5-epi-sinularene () were synthesised in a stereocontrolled manner from the norbornene in overall yields of 4% and 8%, respectively. The key step → involves a regio- and stereoselective intramolecular “magnesium-ene” reaction. 相似文献