89656-36-0Relevant academic research and scientific papers
Stereocontrolled synthesis of bicyclic ureas and sulfamides via Pd-catalyzed alkene carboamination reactions
Babij, Nicholas R.,Boothe, Jordan R.,McKenna, Grace M.,Fornwald, Ryan M.,Wolfe, John P.
, p. 4228 - 4243 (2019/05/04)
The synthesis of bicyclic ureas and sulfamides via palladium-catalyzed alkene carboamination reactions between aryl/alkenyl halides/triflates and alkenes bearing pendant cyclic sulfamides and ureas is described. The substrates for these reactions are gene
A Cross-Metathesis/Aza-Michael Reaction Strategy for the Synthesis of Cyclic and Bicyclic Ureas
Hinds, Elsa M.,Wolfe, John P.
, p. 10668 - 10676 (2018/09/18)
The synthesis of cyclic and bicyclic ureas via a ruthenium-catalyzed cross-metathesis/aza-Michael reaction strategy between protected alkenyl ureas and Michael acceptors is described. The substrates for these reactions are generated in 1-3 steps from comm
Radical allylations by reaction of azides with allylindium dichloride
Bencivenni, Giorgio,Lanza, Tommaso,Minozzi, Matteo,Nanni, Daniele,Spagnolo, Piero,Zanardi, Giuseppe
experimental part, p. 3444 - 3450 (2010/08/21)
Allylindium dichloride is an effective reagent for carrying out photolytically initiated radical allylation reactions, as also proved by EPR experiments. In the presence of suitable azides that can give rise to electrophilic radicals, a homolytic chain reaction occurs with formation of allylated compounds. With δ-azido esters and chlorides generation of primary indiumaminyl radicals is followed by a very efficient 1,5-H shift process that gives rise to electrophilic carbon-centred radicals, whose subsequent allylation by the starting indium reagent, followed by aqueous workup, eventually affords allylated nitrogen heterocycles in good yields. Some comparative theoretical calculations accounted for the observation that analogous reactions with an organoallyltin reagent did not work at all. The results show that the reaction with allylindium dichloride seems strongly favoured by both a lower BDE of the allyl-metal bond and a considerably faster, exothermic 1,5-H migration step. The Royal Society of Chemistry 2010.
Constrained geometry organoactinides as versatile catalysts for the intramolecular hydroamination/cyclization of primary and secondary amines having diverse tethered C-C unsaturation
Stubbert, Bryan D.,Marks, Tobin J.
, p. 4253 - 4271 (2008/02/01)
A series of "constrained geometry" organoactinide complexes, (CGC)An(NMe)2 (CGC = Me2-Si(η5-Me 4C5)(tBuN); An = Th, 1; U, 2), has been prepared via efficient in situ, two-step protodeamination routes in good yields and high purity. Both 1 and 2 are quantitatively converted to the neutrally charged, solvent-free dichlorides (1-Cl2, 2-Cl2) and slightly more soluble diiodides (1-I2, 2-I2) with excess Me3Si-X (X = Cl, I) in non-coordinating solvents. The new complexes were characterized by NMR spectroscopy, elemental analysis, and (for 1 and 2) single-crystal X-ray diffraction, revealing substantially increased metal coordinative unsaturation vs the corresponding Me2SiCp″ 2AnR2 (Cp″ = η5-Me4C 5; An = Th, R = CH2-(SiMe3), 3; An = U, R = CH2Ph, 4) and Cp′2AnR2 (Cp′ = η5-Me5C5 ; An = Th, R = CH 2(SiMe3), 5; An = U, R = CH2(SiMe3), 6) complexes. Complexes 1-6 exhibit broad applicability for the intramolecular hydroamination of diverse C-C unsaturations, including terminal and internal aminoalkenes (primary and secondary amines), aminoalkynes (primary and secondary amines), aminoallenes, and aminodienes. Large turnover frequencies (N t up to 3000 h-1) and high regioselectivities (≥95%) are observed throughout, along with moderate to high diastereoselectivities (up to 90% trans ring closures). With several noteworthy exceptions, reactivity trends track relative 5f ionic radii and ancillary ligand coordinative unsaturation. Reactivity patterns and activation parameters are consistent with a reaction pathway proceeding via turnover-limiting C=C/C=C insertion into the An-N σ-bond.
Phosphorus-derived chiral auxiliaries for α-alkylation of secondary amines by anodic oxidation
Sierecki, Emma,Turcaud, Serge,Martens, Thierry,Royer, Jacques
, p. 3199 - 3208 (2008/09/17)
Chiral phosphorus-based structures were investigated as N-activating groups for anodic oxidation and as chiral inductors. This first study presents the results obtained for pyrrolidine, with allyltrimethylsilane as a standard nucleophile. The methoxylated
Intramolecular Hydroamination/Cyclization of Conjugated Aminodienes Catalyzed by Organolanthanide Complexes. Scope, Diastereo- and Enantioselectivity, and Reaction Mechanism
Hong, Sukwon,Kawaoka, Amber M.,Marks, Tobin J.
, p. 15878 - 15892 (2007/10/03)
Organolanthanide complexes of the general type Cp′ 2LnCH(TMS)2 (Cp′ = η5-Me 5C5; Ln = La, Sm, Y; TMS = SiMe3) and CGCSmN(TMS)2 (CGC = Me2Si(η5-Me 4C5)(tBuN)) serve as effective precatalysts for the rapid, regioselective, and highly diastereoselective intramolecular hydroamination/cyclization of primary and secondary amines tethered to conjugated dienes. The rates of aminodiene cyclizations are significantly more rapid than those of the corresponding aminoalkenes. This dienyl group rate enhancement as well as substituent group (R) effects on turnover frequencies is consistent with proposed transition state electronic demands. Kinetic and mechanistic data parallel monosubstituted aminoalkene hydroamination/cyclization, with turnover-limiting C=C insertion into the Ln-N bond to presumably form an Ln-η3 allyl intermediate, followed by rapid protonolysis of the resulting Ln-C linkage. The rate law is first-order in [catalyst] and zero-order in [aminodiene]. However, depending on the particular substrate and catalyst combination, deviations from zero-order kinetic behavior reflect competitive product inhibition or self-inhibition by substrate. Lanthanide ionic radius effects and ancillary ligation effects on turnover frequencies suggest a sterically more demanding Ln-N insertion step than in aminoalkene cyclohydroamination, while a substantially more negative ΔS? implies a more highly organized transition state. Good to excellent diastereoselectivity is obtained in the synthesis of 2,5-trans-disubstituted pyrrolidines (80% de) and 2,6-cis-disubstituted piperidines (99% de). Formation of 2-(prop-1-enyl)piperidine using the chiral C1-symmetric precatalyst (S)-Me2Si(OHF)(CpR* )SmN(TMS)2 (OHF = η5-octahydrofluorenyl; Cp = η5-C5H3; R* = (-)-menthyl) proceeds with up to 71% ee. The highly stereoselective feature of aminodiene cyclization is demonstrated by concise syntheses of naturally occurring alkaloids, (±)-pinidine and (+)-coniine from simple diene precursors.
Highly stereoselective intramolecular hydroamination/cyclization of conjugated aminodienes catalyzed by organolanthanides
Hong, Sukwon,Marks, Tobin J.
, p. 7886 - 7887 (2007/10/03)
Efficient intramolecular hydroamination/cyclization of primary and secondary conjugated aminodienes can be effected by using organolanthanide precatalysts of the type Cp-2LnCH(TMS)2 (Cp- = η5-Me5C5; Ln = La, Sm, Y; TMS = SiMe3) and CGCSmN(TMS)2 (CGC = Me2Si(η5-Me4C5)(tBuN)). The transformation proceeds cleanly (≥ 90% conversion) at 25-60 °C with good rates and high regioselectivities, and with electronic effects leading to significant rate enhancements. Some features of the reaction parallel monosubstituted aminoalkene hydroamination/cyclization, including rate law (zero order in [aminodiene]), and rate enhancements observed with larger lanthanide ionic radii and/or more open catalyst ligation structures. Good to excellent diastereoselectivity is obtained in the synthesis of 2,5-trans-disubstituted pyrrolidines (80% de) and 2,6-cis-disubstituted piperidines (99% de) with using the corresponding α-methyl aminodiene precursors. Formation of 2-(prop-1-enyl)piperidine with the chiral C1-symmetric precatalyst (S)-Me2Si(OHF)(CpR*)SmN(TMS)2 (OHF = η5-octahydrofluorenyl; Cp = η5-C5H3; R* = (-)-menthyl) proceeds with up to 69% ee. Copyright
Stereoselective synthesis of pyrrolidines and pyrrolizidines by intramolecular carbolithiation
Coldham,Hufton,Price,Rathmell,Snowden,Vennall
, p. 1523 - 1531 (2007/10/03)
Methods for the preparation of substituted homoallylic amines and their conversion to pyrrolidines or pyrrolizidines are described. N-Alkylation of a variety of homoallylic secondary amines with (tributylstannyl)methyl methanesulfonate and subsequent tinlithium exchange, generates organolithium species that undergo intramolecular carbolithiation (anionic cyclization). High stereoselectivities in the cyclization, particularly for the formation of 2,4-disubstituted pyrrolidines, are obtained.
A novel acid stable/base labile carbamate linker for N-acyliminium ion reactions on solid support
Veerman, Johan J. N.,Rutjes, Floris P. J. T.,Van Maarseveen, Jan H.,Hiemstra, Henk
, p. 6079 - 6082 (2007/10/03)
The development of a novel carbamate linker optimized for solid phase N- acyliminium ion chemistry is reported. Some 2- and 2,4-substituted pyrrolidines were synthesized via addition of several carbon nucleophiles to immobilized N-acyliminium ions. A β-sulfonylethyl carbamate linker appeared especially useful; readily synthesized, stable towards Lewis acids and easily cleavable.
SYNTHESIS OF 7-AZABICYCLOHEPTANE AND 8-AZABICYCLOOCTANE SYSTEMS USING RADICAL CYCLIZATION
Sato, Tatsunori,Mori, Tomiyo,Sugiyama, Tadakatsu,Ishibashi, Hiroyuki,Ikeda, Masazumi
, p. 245 - 248 (2007/10/02)
A new method for the synthesis of the titled systems using cyclization of the α-acylamino radicals generated from methyl N-(o-bromobenzoyl)-2-(prop-2-enyl)pyrrolidine-2-carboxylates and the piperidine congener by Bu3SnH-mediated radical translocation reaction is described.
