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James L Wardell - One of the best experts on this subject based on the ideXlab platform.
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synthesis of bis tert butyl 2 thioxo 1 3 dithiole 4 5 dithiolato Stannane but2sn dmit and bis tert butyl 2 oxo 1 3 dithiole 4 5 dithiolato Stannane but2sn dmio crystal structures at 120 k of polymeric but2sn dmit and two polymorphs of but2sn dmio a p
Journal of Organometallic Chemistry, 2008Co-Authors: Nadia M Comerlato, Glaucio B Ferreira, Alan R Howie, Carolina X A Da Silva, James L WardellAbstract:Abstract The syntheses of bis(tert-butyl)(2-thioxo-1,3-dithiole-4,5-dithiolato)Stannane, But2Sn(dmit) 1, and bis(tert-butyl)(2-oxo-1,3-dithiole-4,5-dithiolato)Stannane, But2Sn(dmio) 2, are reported. Compounds 1 and 2 were prepared by the exchange reactions of But2SnCl2 with [NEt4]2[Zn(dmit)2] and [NEt4]2[Zn(dmio)2], respectively. X-ray structure determinations reveal the existance of two polymorphs of 2, 2m and 2o. In all three phases, intermolecular Sn–Sthioxo or Sn–Ooxo, as appropriate, create five-coordinate, trigonal bipyramidal tin centres. In 1 and 2o these intermolecular contacts link the molecules in chains, while in 2m they create a centrosymmetric cyclic tetramer, with a 24 membered, Sn4C8O4S8, ring. These findings of aggregated structures are in contrast to the published report that the simpler ethane-1,2-dithiolato compound, But2Sn(edt), is a molecular species in the solid state.
Nadia M Comerlato - One of the best experts on this subject based on the ideXlab platform.
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synthesis of bis tert butyl 2 thioxo 1 3 dithiole 4 5 dithiolato Stannane but2sn dmit and bis tert butyl 2 oxo 1 3 dithiole 4 5 dithiolato Stannane but2sn dmio crystal structures at 120 k of polymeric but2sn dmit and two polymorphs of but2sn dmio a p
Journal of Organometallic Chemistry, 2008Co-Authors: Nadia M Comerlato, Glaucio B Ferreira, Alan R Howie, Carolina X A Da Silva, James L WardellAbstract:Abstract The syntheses of bis(tert-butyl)(2-thioxo-1,3-dithiole-4,5-dithiolato)Stannane, But2Sn(dmit) 1, and bis(tert-butyl)(2-oxo-1,3-dithiole-4,5-dithiolato)Stannane, But2Sn(dmio) 2, are reported. Compounds 1 and 2 were prepared by the exchange reactions of But2SnCl2 with [NEt4]2[Zn(dmit)2] and [NEt4]2[Zn(dmio)2], respectively. X-ray structure determinations reveal the existance of two polymorphs of 2, 2m and 2o. In all three phases, intermolecular Sn–Sthioxo or Sn–Ooxo, as appropriate, create five-coordinate, trigonal bipyramidal tin centres. In 1 and 2o these intermolecular contacts link the molecules in chains, while in 2m they create a centrosymmetric cyclic tetramer, with a 24 membered, Sn4C8O4S8, ring. These findings of aggregated structures are in contrast to the published report that the simpler ethane-1,2-dithiolato compound, But2Sn(edt), is a molecular species in the solid state.
Eric J Thomas - One of the best experts on this subject based on the ideXlab platform.
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remote stereocontrol using e 6 hydroxy 4 methylhex 2 enyl tri n butyl Stannane
Journal of Organometallic Chemistry, 2006Co-Authors: Somhairle Maccormick, Eric J ThomasAbstract:Reactions of (E)-6-hydroxy-4-methylhex-2-enyl(tributyl)Stannane (11) with aldehydes, when promoted by tin(IV) bromide, proceed with effective 1,5-stereocontrol to give (Z)-1,5-anti-5-methylhept-3-ene-1,7-diols (23), suitable precursors for the stereoselective synthesis of eight-membered lactones.
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1 6 asymmetric induction in reactions between 6 hydroxy 5 methylhex 2 enyl tributyl Stannane and aldehydes promoted by tin iv bromide
Tetrahedron Letters, 1995Co-Authors: Steve J Stanway, Eric J ThomasAbstract:(R)-6-Hydroxy-5-methylhex-2-enyl(tributyl)Stannane 4 transmetallates on treatment with tin(IV) bromide to give an intermediate allyltin tribromide which reacts with aldehydes to give 1-substituted (Z)-6-methylhept-2-ene-1,7-diols 7 with excellent anti-1,6-asymmetric induction.
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1 5 asymmetric induction in reactions between aldehydes and 4s 5 tert butyldimethylsilyloxy 4 hydroxypent 2 enyl tributyl Stannane promoted by tin iv chloride
Journal of The Chemical Society-perkin Transactions 1, 1995Co-Authors: Robert J Maguire, Eric J ThomasAbstract:[(4S)-5-(tert-Butyldimethylsilyloxy)-4-hydroxypent-2-enyl](tributyl)Stannane 18 has been prepared from di-O-isopropylidene-D-mannitol 8. Oxidative cleavage of the mannitol derivative followed by condensation with triethyl phosphonoacetate and reduction gave the alcohol 10 which was converted into the xanthate 11. Deprotection gave the dihydroxy xanthate 12 which was protected as its bis-tert-butyldimethylsilyl ether 13. This rearranged on heating in toluene to give the dithiocarbonate 15 which reacted with tributyltin hydride under free radical conditions to give the [(4S)-4,5-bis(tert-butyldimethylsilyloxy)pent-2-enyl](tributyl)Stannane 16 as an approximately 9:1 mixture of E- and Z-isomers. Deprotection and selective protection of the primary hydroxy group provided the [(4S)-5-(tert-butyldimethylsilyloxy)-4-hydroxypent-2-enyl]Stannane 18. As a shorter route, the primary hydroxy group of the dihydroxy xanthate 12 was protected as its tert-butyldimethylsilyl ether 14 which underwent clean rearrangement into the dithiocarbonate 19 when heated in toluene. Reaction with tributyltin hydride under free radical conditions then gave the (5-tert-butyldimethylsilyloxy-4-hydroxypent-2-enyl)Stannane 18. Treatment of this 4,5-disubstituted pentenylStannane with tin(IV) chloride generated an allyltin trichloride which reacted with aldehydes with excellent 1,5-asymmetric induction to give 1,5-syn-products, e.g. 20, 29–31 and 41. The stereoselectivity of these reactions would appear to be controlled by the 4-hydroxy substituent rather than by the 5-tert-butyldimethylsilyl group. Aspects of the chemistry of these products, in particular their conversion into 2,6-disubstituted 5,6-dihydro-2H-pyrans, was investigated.
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15-asymmetric induction in reactions between (alkoxyallyl)Stannanes and aldehydes: Influence of the Lewis acid and -substituent
Tetrahedron Letters, 1993Co-Authors: John S. Carey, Thomas S. Coulter, Eric J ThomasAbstract:Abstract The influence of the Lewis acid and the O -substituent on the efficiency of the remote asymmetric induction observed in reactions between (alkoxyallyl)Stannanes and aldehydes has been investigated.
James A. Marshall - One of the best experts on this subject based on the ideXlab platform.
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The BF3 and B(C6F5)3-catalyzed 1,3-isomerization of allylic Stannanes
Journal of Organometallic Chemistry, 2001Co-Authors: James A. Marshall, Kevin GillAbstract:Abstract A spectroscopic and chemical study of the stereospecific B(C6F5)3-catalyzed 1,3-isomerization of (E,S)-1-methoxymethoxy-2-butenyl tributylStannane to (Z,S)-1-methyl-3-methoxymethoxy-2-propenyl tributylStannane is described. A pathway involving an intermediate B(C6F5)3 adduct is proposed based upon 1H- and 119Sn-NMR data. Analogous spectral evidence was not observed in the seemingly related BF3·OEt2-catalyzed isomerization. However, the similar product ratios obtained in B(C6F5)3 and BF3·OEt2-promoted additions of the latter Stannane to o- and p-methoxybenzaldehyde reveals a close similarity between the two and prompts speculation that the BF3·OEt2-catalyzed 1,3-isomerization proceeds by an analogous pathway. A pathway for the B(C6F5)3-promoted addition of allylic Stannanes to o-methoxybenzaldehyde is also presented.
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Highly syn-Selective Additions of Allylic Stannanes to Protected .alpha.-Amino Aldehydes
Journal of Organic Chemistry, 1994Co-Authors: James A. Marshall, Boris M. Seletsky, Paul S. CoanAbstract:The γ-oxygenated allylic Stannane (R)-(8b) adds to the threonine- and serine-derived N-BOC aldehydes (1) and (14) in the presence of MgBr 2 to afford the syn adducts 9b and 15b as the sole products
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Enantioselective Synthesis of (+)- and (-)-Muricatacin through SE2' Addition of Nonracemic .gamma.-Silyloxy Allylic Stannanes to Aldehydes
Journal of Organic Chemistry, 1994Co-Authors: James A. Marshall, Gregory S. WelmakerAbstract:The acetogenins (R,R)-(+)- and (S,S)-(-)-muricatacin were synthesized through the highly stereo-selective addition of γ-silyloxy allylic Stannanes (S)-6 and (R)-6 to (E)-ethyl 3-formylpropenoate (12) in the presence of BF 3 -OEt 2 . The resulting adducts (R,R)-13 and (S,S)-13 afforded the aforementioned acetogenins upon catalytic hydrogenation and subsequent deprotection-lactonization with aqueous HF. Interestingly, additions of Stannanes 6 (racemic) to the saturated aldehydes RCH 2 CH 2 CHO (8, R=CO 2 Et, R=CN, R=Cl in the presence of BF 3 -OEt 2 afforded ca. 70:30 mixtures of syn and anti adducts 9a-c. In contrast, the n-alkyl aldehyde 8 (R=n-C 4 H 9 ) underwent highly selective syn addition (97:3) with the crotyl analogue 7 of Stannane 6
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stereoselective total synthesis of bengamide e from glyceraldehyde acetonide and a nonracemic gamma alkoxy allylic Stannane
Journal of Organic Chemistry, 1993Co-Authors: James A. Marshall, George P LukeAbstract:The synthesis of bengamide E (30) was achieved starting from the furan adduct 1 of (R)-glyceraldehyde acetonide. The key step entailed MgBr 2 -promoted addition of the (S)-γ-alkoxy allylic Stannane (S)-25 to the aldehyde 8 obtained from the oxidation product of furan 1 after protection as the methyl ether. The adduct of Stannane (S)-25 and aldehyde 8, a 1:1 mixture of hydroxy ester 27 and lactone 28 was converted to bengamide E by aminolysis with (S)-2-aminocaprolacm and subsequent debenzylation with Li in NH 3
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(Z)- and (E)-.gamma.-silyloxy allylic Stannanes. Highly syn selective reagents for SE' additions to aldehydes
Journal of Organic Chemistry, 1992Co-Authors: James A. Marshall, Gregory S. WelmakerAbstract:The (E)-γ-silyloxy allylic Stannane 2E, available in one step through addition of Bu(Bu 3 Sn)Cu(CN)Li 2 to crotonaldehyde and subsequent in situ quenching of the enolate with t-BuMe 2 SiCl, undergoes BF 3 -promoted addition to representative aldehydes 3a-e, affording syn adducts 4a-e with >99:1 diastereoselectivity. The (Z)-γ-silyloxy allylic Stannane 2Z can be prepared by treatment of the adduct from Bu 3 SnLi and crotonaldehyde with TBSOTf in the presence of i-Pr 2 NEt. Stannane 2Z also affords syn adducts upon BF 3 -promoted addition to aldehydes 3a-e but with somewhat lower diastereoselectivity (93:7-99:1)
Ronald Breslow - One of the best experts on this subject based on the ideXlab platform.
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a water soluble tin hydride tris 3 2 methoxyethoxy propyl Stannane
Organic Syntheses, 2003Co-Authors: James Light, Ronald BreslowAbstract:A water-soluble tin hydride: tris[3-(2-methoxyethoxy)propyl]Stannane intermediate: 3-(2-Methoxyethoxy)propene (1) intermediate: 1-Bromo-3-(2-methoxyethoxy)propane (2) intermediate: Tetra[3-(2-methoxyethoxy)propyl]Stannane (3) intermediate: Bromotris[3-(2-methoxyethoxy)propyl]Stannane (4) intermediate: Tris[3-(2-methoxyethoxy)propyl]Stannane (5) Keywords: addition, to CC; alkylation, O-alkylation; etherification; halogenation, bromination; hydroboration; metalation reactions, magnesium; metalation reactions, tin; reduction, miscellaneous; replacement reactions, halogen by various groups; 1,2-dimethoxyethane, purification of; tetrahydrofuran; bromine; bromine; carbon tetrachloride, cancer suspect agent; organotin compounds, highly toxic; tin alkyls
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Organic Syntheses - A Water‐Soluble Tin Hydride: Tris[3‐(2‐Methoxyethoxy)Propyl]Stannane
Organic Syntheses, 2003Co-Authors: James Light, Ronald BreslowAbstract:A water-soluble tin hydride: tris[3-(2-methoxyethoxy)propyl]Stannane intermediate: 3-(2-Methoxyethoxy)propene (1) intermediate: 1-Bromo-3-(2-methoxyethoxy)propane (2) intermediate: Tetra[3-(2-methoxyethoxy)propyl]Stannane (3) intermediate: Bromotris[3-(2-methoxyethoxy)propyl]Stannane (4) intermediate: Tris[3-(2-methoxyethoxy)propyl]Stannane (5) Keywords: addition, to CC; alkylation, O-alkylation; etherification; halogenation, bromination; hydroboration; metalation reactions, magnesium; metalation reactions, tin; reduction, miscellaneous; replacement reactions, halogen by various groups; 1,2-dimethoxyethane, purification of; tetrahydrofuran; bromine; bromine; carbon tetrachloride, cancer suspect agent; organotin compounds, highly toxic; tin alkyls
