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Search for "tin" in Full Text gives 138 result(s) in Beilstein Journal of Organic Chemistry.
Recent advances in carbocupration of α-heterosubstituted alkynes
Beilstein J. Org. Chem. 2010, 6, No. 77, doi:10.3762/bjoc.6.77
- wide range of electrophiles to afford regio- and stereodefined vic- and gem-silyl (and tin) trisubstituted alkenes (Scheme 24). Even the deactivated bis-trimethylsilylacetylene reacted the dimethylphenylsilylcuprate reagent in presence of TMEDA to afford the trisilylalkene in moderate yield [60
Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length
Beilstein J. Org. Chem. 2010, 6, No. 67, doi:10.3762/bjoc.6.67
- which significantly exceed the molecular weight of processable oligomeric linear PGA (<1000 g/mol). This was achieved by the use of a multifunctional hyperbranched polyglycerol (PG) macroinitiator and the tin(II)-2-ethylhexanoate catalyzed ring-opening polymerization of glycolide in the melt. With this
- purified by vacuum distillation over CaH2 directly prior to use. Tetrahydrofuran (THF) was refluxed with sodium/benzophenone before distillation. Glycolide was purchased from Purac®/Gorinchem (Netherlands) and used as received. Tin(II)-2-ethylhexanoate (Sn(Oct)2), 97% was obtained from Acros and used as
Self-assembled ordered structures in thin films of HAT5 discotic liquid crystal
Beilstein J. Org. Chem. 2010, 6, No. 51, doi:10.3762/bjoc.6.51
- between indium tin oxide (ITO)-coated glass plates at micrometer distance, very little is known about the organization of HAT5 in films of submicrometer thickness and their characteristics. Such films, produced by drop-casting and spin-coating, are the focus of this study. Results and Discussion Different
- on square glass substrates of 2.5 cm side length, coated with indium tin oxide (ITO). The deposition of the solution was performed by drop-casting or spin-coating, the latter at a speed of 500 rpm for 10 s. A starting concentration of 7.2 mg/ml was initially chosen to ensure a macroscopic coverage of
Synthesis and Diels–Alder cycloaddition reaction of norbornadiene and benzonorbornadiene dimers
Beilstein J. Org. Chem. 2009, 5, No. 39, doi:10.3762/bjoc.5.39
- 7 and 8 with PTAD (9) and TCNE (10) resulted in the formation of the corresponding products 11–14 in high yields (Scheme 2). Similarly, tin compound 15 was synthesized by the reaction of monobromide 5 with n-BuLi followed by reaction with trimethyltin chloride. Reaction of 15 with Cu(NO3)2·3H2O
Radical carbonylations using a continuous microflow system
Beilstein J. Org. Chem. 2009, 5, No. 34, doi:10.3762/bjoc.5.34
- demonstrated by our group [4][5][6] as well as others [7][8][9][10][11]. In our recent report, we demonstrated that excellent thermal efficiency of the microflow system would lead to effective execution of tin hydride and TTMSS (tris(trimethylsilyl)silane)-mediated radical reduction and cyclization reactions
- yields of the desired products. Carbon monoxide is an important feedstock and our group has actively pursued carbonylation reactions [14][15][16][17]. Thermally induced radical carbonylations using tin hydride usually require pressurized CO conditions to ensure that the concentration of CO around the
- radical centers is high enough to compete with the premature quenching by tin hydride (Scheme 1). Encouraged by our previous successes with both radical reactions [12] and metal-catalyzed carbonylation reactions using microflow devices [18][19][20], we decided to examine a continuous microreaction system
Recent progress on the total synthesis of acetogenins from Annonaceae
Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48
Synthesis of chiral cyclohexanes and carbasugars by 6-exo-dig radical cyclisation reactions
Beilstein J. Org. Chem. 2008, 4, No. 43, doi:10.3762/bjoc.4.43
- is some 40 times slower than the counterpart 5-hexenyl cyclisation [15][16][17][18][19]. In the case of the 6-hexenyl radical this results in the attack of the acyclic radical on the tin reagent becoming a more effective process compared to the 5-hexenyl case. An additional problem is that a 1,5
Part 1. Reduction of S-alkyl- thionocarbonates and related compounds in the presence of trialkylboranes/air
Beilstein J. Org. Chem. 2007, 3, No. 45, doi:10.1186/1860-5397-3-45
- and its efficiency. However, this procedure suffers from crippling drawbacks in terms of toxicity, cost, disposal, and tedious purification to remove tin residues. [6][7][8][9][10] However, we recently faced limits to the use of some of these methods for reductive removal of S-alkyl O-ethyl
Solvent- controlled regioselective protection of allyl- 4,6-benzylidene glucopyranosides
Beilstein J. Org. Chem. 2007, 3, No. 26, doi:10.1186/1860-5397-3-26
- functional group manipulations required to access suitable synthetic precursors. For hexopyranoses, acylation of cis-diols can be achieved with high regioselectivity either by means of metal activators such as tin [1][2][3], silver [4], boron [5] or copper [6] or by exploiting the relative reactivity of
- hydroxyl groups [7][8]. However, metal-promoted alkylation and base-catalysed acylation of diols have proven to be highly undependable in the case of glucose and other cyclic trans-diols, where both hydroxyl groups are equatorial. For instance, reports of identical procedures describing the tin-catalysed
The use of silicon- based tethers for the Pauson- Khand reaction
Beilstein J. Org. Chem. 2007, 3, No. 21, doi:10.1186/1860-5397-3-21
- and Hunig's base; tin (IV) chloride[27] and N-bromosuccimide[28] were all tested but none were successful as either no reaction occurred or the alkene was halogenated as well as the conversion of the silane to the silyl chloride. Further, given that the major product from many of the methods attempted
Allylsilanes in the synthesis of three to seven membered rings: the silylcuprate strategy
Beilstein J. Org. Chem. 2007, 3, No. 16, doi:10.1186/1860-5397-3-16
- key step is the syn addition of the tin cuprate to the acetylene, which controls the cis stereochemistry required for cyclization. [23] Seven Membered Carbocycles The use of nitriles and imines as electrophiles in the silylcupration of allene provides new alternatives for carbocyclization. Recently
Generation of pyridyl coordinated organosilicon cation pool by oxidative Si-Si bond dissociation
Beilstein J. Org. Chem. 2007, 3, No. 7, doi:10.1186/1860-5397-3-7
- was found that the introduction of a coordinating group such as a pyridyl group decreased the oxidation potential of tetraalkylstannanes, although there is no indication of the coordination in the neutral molecule. Dynamic intramolecular coordination to tin seems to facilitate electron transfer [22
Do α-acyloxy and α-alkoxycarbonyloxy radicals fragment to form acyl and alkoxycarbonyl radicals?
Beilstein J. Org. Chem. 2006, 2, No. 10, doi:10.1186/1860-5397-2-10
- provide unequivocal evidence for the fragmentation of such radicals to give ketones and acyl or alkoxycarbonyl radicals. Instead, standard reduction predominates, even at low tin hydride concentrations. Some ketone product is formed in the α-acyloxy substrate at low concentrations, but it is unclear
- give 15 and 16a,b is the competition step, and a standard plot of the ratio of products as a function of tin hydride concentration should provide a straight line passing through the origin if radical fragmentation competes with reduction. Alternatively, oxidation of 13a,b to cation 17a,b will
- conditions, as detailed in the Supporting Information. Briefly, stock solutions of the iodide 11a,b (1 equiv) and Bu3SnH (1.1 equiv) in C6H6 or C6D6 were diluted to the required concentration of tin hydride, then AIBN (0.2 equiv) and p-dimethoxybenzene (0.1–0.2 equiv, internal standard) were added. The
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