186755-00-0Relevant academic research and scientific papers
Chemoselective and Diastereoselective Intramolecular (3+2) Cycloadditions of Epoxy and Aziridinyl Enolsilanes
Chen, Yueyao,Chiu, Pauline,He, Yun,Keto, Angus B.,Krenske, Elizabeth H.,Ling, Jesse,Low, Kam-Hung
supporting information, (2022/03/31)
Epoxy and aziridinyl enolsilanes react as oxyallylic cation equivalents in highly chemo- and diastereoselective intramolecular (3+2) cycloadditions with a range of dienes and olefins. With acyclic dienes, the (3+2) cycloaddition outcompetes the (4+3) pathway traditionally observed in this kind of system almost exclusively. With both conjugated dienes and isolated olefins, excellent diastereoselectivities are observed, and cycloadducts can be obtained in optically-enriched forms. Computational studies indicate that the stepwise (3+2) cycloaddition involves an activated epoxy/aziridinyl intermediate and the conformational flexibility of the intermediate determines the preference for (3+2) cycloadduct formation. Further transformations of the (3+2) cycloadducts produce densely functionalized trans-hydrindane scaffolds.
Intramolecular nitroalkene diels-alder reaction catalyzed by br?nsted acids
Aguado, Andreina,Takenaka, Norito
, p. 1259 - 1261 (2011/07/06)
Br?nsted acid catalysis of intramolecular Diels-Alder cyclizations of (E)-1-nitro-1,6,8-nonatrienes and (E)-1-nitro-1,7,9-decatrienes was investigated. Catalyzed reactions showed significantly higher endo selectivities than the corresponding thermal react
Facile C-N cleavage in a series of bridged lactams
Lei, Yao,Wrobleski, Aaron D.,Golden, Jennifer E.,Powell, Douglas R.,Aube, Jeffrey
, p. 4552 - 4553 (2007/10/03)
A series of strained bi- and tricyclic amides has been shown to be unusually sensitive to cleavage of the C-N bond adjacent to the amide moiety. This bond undergoes facile breaking when subjected to treatment with H2/Pd(OH)2, MeI, and DDQ. In each case, the reaction is highly regioselective and mainly results in breaking the C-N bond that deviates the farthest from its natural planar state. Preliminary experiments that bear on the mechanisms of these reactions are described. Copyright
Stille reactions catalytic in tin: A "Sn-F" route for intermolecular and intramolecular couplings
Gallagher, William P.,Maleczka Jr., Robert E.
, p. 841 - 846 (2007/10/03)
(Chemical Equation Presented) Polymethylhydrosiloxane (PMHS) made hypercoordinate by KF(aq) allows Me3SnH to be recycled during a Pd(0)-catalyzed hydrostannation/Stille cascade. Starting with a variety of alkynes, in situ vinyltin formation is followed by Stille reaction with aryl, styryl, benzyl, or vinyl electrophiles present in the reaction mixture. Both inter- and intramolecular versions of the process are possible with tin loads of approximately 6 mol %. Regeneration of the organotin hydride is believed to proceed through a Me3SnF intermediate. Given the aggregated nature of organotin fluorides and the ability to use these organotins in substoichiometric quantities, the hazards and purification problems associated with the removal of organotin wastes from reaction mixtures are minimized.
Stille couplings catalytic in tin: a "Sn-F" approach.
Maleczka Jr.,Gallagher
, p. 4173 - 4176 (2007/10/03)
A new tin recycling method for Stille couplings catalytic in tin is reported. PMHS made hypercoordinate by KF((aq)) allows Me(3)SnH to be efficiently recycled during a Pd(0)-catalyzed hydrostannation/Stille cascade. Relative to previously disclosed protoc
Stille couplings catalytic in tin: The "Sn-O" approach
Gallagher,Terstiege,Maleczka Jr.
, p. 3194 - 3204 (2007/10/03)
A one-pot tandem Pd-catalyzed hydrostannylation/Stille coupling protocol for the stereoselective generation of vinyltins and their subsequent union, employing only catalytic amounts of tin, is described. By recycling the organotin halide Stille byproduct back to organotin hydride, a hydrostannylation/cross-coupling sequence can be carried out with catalytic amounts of tin. Such a process is most effective with Me3SnCl serving as the tin source. This protocol allows a 94% reduction of the tin requirement, while maintaining good yields (up to 90%) for a variety of Stille products. Furthermore, since one cycle requires the tin to undergo at least four transformations, each moiety of trialkyltin is experiencing a minimum of 60 reactions over the course of the hydrostannylation/Stille, sequence.
Bis(oxazoline) and bis(oxazolinyl)pyridine copper complexes as enantioselective Diels-Alder catalysts: Reaction scope and synthetic applications
Evans, David A.,Barnes, David M.,Johnson, Jeffrey S.,Lectka, Thomas,Von Matt, Peter,Miller, Scott J.,Murry, Jerry A.,Norcross, Roger D.,Shaughnessy, Eileen A.,Campos, Kevin R.
, p. 7582 - 7594 (2007/10/03)
The scope of the Diels-Alder reaction catalyzed by bis(oxazoline) copper complexes has been investigated. In particular, [Cu((S,S)-t-Bu-box)](SbF6)2 (1b) has been shown to catalyze the Diels-Alder reaction between 3-propenoyl- 2-oxaz
