Allyltri-n-butyltin

Allylboronates of type 103 react with equivalent amounts of aldoximes 102 (equation 73) giving allylhydroxylamines 104 in good yields. Similar reactions of aldoximes and glyoxylate oxime ethers with allyl bromide and indium also provide hydroxylamines. Additions of substituted allyl boronates to oximes produce mixtures of stereoisomers with ratio highly dependent on the steric size of substituents in both molecules. Addition of allyltri-n-butyltin to aldoxime ether 105 (equation 74) was found to proceed with a considerable diastereoselectivity. 

Allyl phosphates, 506 Allylsilanes, 43, 71-72, 529, 575 Allyl sulfones, 512 Allyltitaniiun ate complexes, 376-377 Allyltri-n-butyltin, 15-16 Allyltrimethylsilane, 16-20, 532 Allyltrimethyltin, 20-21 Almusone, 51 Alpine Boranc, 429 Alumina, 22-24 Aluminum amalgam, 24-25 Aluminum ate complexes, 17 Aluminum chloride, 25-28, 100 Aluminum chloride-ethanethiol, 28-29 Aluminum isopropoxide, 29, 296 Amidoalkylation, 16-17 Amidomercuration, 317 Animation, 221 Amino acid esters, 360... 

The sterochemistry of additions of allyltri-n-butyltin (1) and crotyltri-n-butyltin (5) with 3-alkoxy aldehydes is more complex. In the allyltin reactions, useful diastereofacial selectivity is observed only with TiCU (4.6 1) or SnCU (9 1). Optimum stereoselectivity in the reaction of the p-alkoxy aldehyde 11 with 5 is observed in the reaction catalyzed by BF, etherate, which results mainly in the product of Cram-Felkin control (equation I). The highest chelation-controlled selectivity in reactions of 5 with the p-benzyloxy aldehyde 12 is obtained with MgBr, (equation II). 

Al.LYI.IC alcohols Allyltri-n-butyltin. Aluminum chloride. Chromium(II) chloride. 

HOMOALLYLIC alcohols B-Allyldiisopino-campheylborane. Allyl phenyl selenide. Allyltri-n-butyltin. Chromium(II) chloride. Crotyltrimethylsilane. Diethyl(tributyl-stannyl)aluminum. (2R, 4R)-Pentanediol. Pinacol chloromethaneboronate. Tin-Alu-minum. Titanium(IV) chloride. 

The reactions of allyltrialkylstannanes with dialdose derivatives proceed similarly, with a high di-astereofacial selectivity in 5.0 M LPDE via chelation-controlled catalysis by the lithium ion. For example, the galactose derivative (4) (1.0 M in ether) reacts with 1.5 equivalents of allyltri-n-butyltin in 5.0 M LPDE, giving rise after 1 h to 96% yield of 5 and 6 in a ratio 25 1, respectively (Scheme 6.3.3). Exposure of (4) to allyltrimethyltin in 5.0 M LPDE proceeded with a high diastereofacial selectivity >25 1. In contrast, treatment of (4) with allyltrimethyltin in 2.0 M LPDE at ambient temperature proceeded with reduced diastereofacial selectivity, giving rise to a 12 1 ratio of (5) and (6), respectively, in only 66% yield. 

Scheme 6.3.3 The allylation of 2,2,7,7-tetramethyl-tetrahydro-bis[l,3]dioxolo[4,5-b 4 5 -d]pyran-5-carbaldehyde with allyltri-n-butyltin...

Table 6.3.5 Metal perchlorate-promoted reaction of allyltri-n-butyltin towards benzaldehyde...

Nishigaichi has described how allylic tin compounds, in the presence of various metal perchlorates, undergo efficient regio- and stereochemical isomerization. In this connection, the reaction of allyltri-n-butyltin with benzaldehyde in ether in the presence of LiClO was examined (Table 6.3.5). 

From a competitive experiment, the reactivity toward benzaldehyde of (2-i-butylallyl)tri-n-butyltin was found to be nearly equal to that of allyltri-n-butyltin in the typically Lewis acid-promoted reaction. In contrast, in the metal perchlorate-promoted reactions, the former was found to be less than one tenth (LiC104) and ca. one quarter [Mg(C104)2] of the latter it seems that in a congested cyclic transition state, the steric... 

Kinart compared the reactivity of allyldi-n-butyltin chloride and allyltri-n-butyltin towards n-hexanal in 4 M LiC104 in diethyl ether. The reaction mixtnres were prepared by dissolving 1 mmol of n-hexanal and an eqnimolar amonnt of allyltin componnd in 2 cm of diethyl ether or in 2 cm of 4 M LPDE. The reactions were carried out over 24 h at room temperature. The obtained results show that the presence of lithium perchlorate in the solution improves considerably the yield of alcohol formed during the allylstannation. In pure diethyl ether at 25 °C the addition proceeds for allyldi-n-butyltin chloride with only 50% yield, whereas in 4 M LPDE the yield of reaction increases to 100%, and for allyltri-n-butyltin it achieves a value of 20%. 

Shown in Fig. is the "time zero" result of transmetala-tion of SnCl4 with allyltri-n-butyltin. Unfortunately, in... 

Allyltri-n-butyltin has been used as a synthetic intermediate in the preparation of 4-butenylketones (from a-chloroketones and AIBN), allylperoxides [a-chloroketones and (PhaP)4Pd] and of allyl substituted p-quinones, notably coenzyme Q, and plastiquinone-1. Dibenzoylperoxide cleaves the allyl-tin bond of allylSnMeg through a cyclic transition state, while (3-trimethylsilyl)cyclo-... 

C-Glycosides.4 Thiophenyl glycosides undergo ready free-radical allylation with allyl- or methallyltri-n-butyltin. Thus the L-lyxose derivative 1 reacts with allyltri-w-butyltin under photochemical initiation to give 2 and 3 in the ratio 90 10. The reaction... 

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