781-06-6Relevant academic research and scientific papers
Regioselective Epoxidations by Cytochrome P450 3A4 Using a Theobromine Chemical Auxiliary to Predictably Produce N-Protected β- or γ-Amino Epoxides
Polic, Vanja,Cheong, Kin Jack,Hammerer, Fabien,Auclair, Karine
supporting information, p. 3983 - 3989 (2017/11/30)
N-Protected β- and γ-amino epoxides are useful chiral synthons. We report here that the enzyme cytochrome P450 3A4 can catalyze the formation of such compounds in a regio- and stereoselective manner, even in the presence of multiple double bonds or aromatic substituents. To this end, the theobromine chemical auxiliary is used not only to control the selectivity of the enzyme, but also as a masked amine, and to facilitate product recovery. Theobromine predictably directed epoxidation at the double bond of the fourth carbon from the theobromine group. Unlike with most catalysts, the selectivity did not depend on electronic or steric factors but rather on the position of the olefin relative to the theobromine group. (Figure presented.).
Reversible C-C bond activation enables stereocontrol in Rh-catalyzed carbonylative cycloadditions of aminocyclopropanes
Shaw, Megan H.,McCreanor, Niall G.,Whittingham, William G.,Bower, John F.
supporting information, p. 463 - 468 (2015/01/30)
Upon exposure to neutral or cationic Rh(I)-catalyst systems, amino-substituted cyclopropanes undergo carbonylative cycloaddition with tethered alkenes to provide stereochemically complex N-heterocyclic scaffolds. These processes rely upon the generation and trapping of rhodacyclopentanone intermediates, which arise by regioselective, Cbz-directed insertion of Rh and CO into one of the two proximal aminocyclopropane C-C bonds. For cyclizations using cationic Rh(I)-systems, synthetic and mechanistic studies indicate that rhodacyclopentanone formation is reversible and that the alkene insertion step determines product diastereoselectivity. This regime facilitates high levels of stereocontrol with respect to substituents on the alkene tether. The option of generating rhodacyclopentanones dynamically provides a new facet to a growing area of catalysis and may find use as a (stereo)control strategy in other processes.
An asymmetric total synthesis of (+)-pentalenene
Kim, Yoon-Jung,Yoon, Yeokwon,Lee, Hee-Yoon
, p. 7810 - 7816 (2013/08/23)
A stereoselective total synthesis of (+)-pentalenene was achieved through the tandem cycloaddition reaction of the allenyl diazo substrate prepared from (+)-citronellal. The initial intramolecular [2+3] cycloaddition reaction between the diazo functionality and the allenyl group produced the trimethylenemethane (TMM) intermediate after immediate loss of nitrogen molecule from the cycloaddition intermediate. Subsequent [2+3] cycloaddition of the TMM with olefin produced the angularly fused triquinane structure stereoselectively.
A Functional-Group-Tolerant Catalytic trans Hydrogenation of Alkynes
Radkowski, Karin,Sundararaju, Basker,Fuerstner, Alois
supporting information, p. 355 - 360 (2013/02/23)
Against the rules: During the hundred years following Sabatier's groundbreaking work on catalytic hydrogenation, syn delivery of the H atoms to the π system of a substrate remained the governing stereochemical rule. An exception has now be found with the
Unexpected formation of a trans-syn-fused linear triquinane from a trimethylenemethane (TMM)-diyl-mediated [2+3] cycloaddition reaction
Kim, Won-Yeob,Kim, Byung Gyu,Kang, Taek,Lee, Hee-Yoon
supporting information; experimental part, p. 1931 - 1935 (2011/12/01)
trans-Fused triquinane: Intramolecular-trimethylenemethane-mediated [2+3] cycloaddition reaction of a highly congested substrate proceeded stepwise to produce highly strained triquinane structures along with tricyclo[5.3.1.0 2, 6]undecanes.
A detailed investigation of the aza-prins reaction
Dobbs, Adrian P.,Guesne, Sebastien J. J.,Parker, Robert J.,Skidmore, John,Stephenson, Richard A.,Hursthouse, Mike B.
supporting information; experimental part, p. 1064 - 1080 (2010/06/13)
The development of a Lewis acid-promoted aza-Prins reaction to form piperidines and pyrrolidines is described. Indium trichloride has been found to be a highly successful and mild Lewis acid for promoting this reaction. A thorough mechanistic investigation is described, including the factors that influence the formation of the 5- or 6-membered ring product(s). The Royal Society of Chemistry.
A mechanistic alternative for the intramolecular hydroboration of homoallylic amine and phosphine borane complexes
Scheideman, Matthew,Shapland, Peter,Vedejs, Edwin
, p. 10502 - 10503 (2007/10/03)
Intramolecular hydroboration is demonstrated starting from homoallylic amine boranes upon activation by iodine. The process involves a B-iodoborane complex as the intermediate and may occur via internal displacement of iodide by the alkene to generate a cationic borane-alkene π-complex on the way to hydroboration products. The reaction can be carried out using a catalytic amount of iodine. Copyright
Intramolecular N-(Acyloxy)iminium Ion-Alkyne Cycloadditions. A New Route to Bicyclic α-Amino Ketones
Fisher, Matthew J.,Overman, Larry E.
, p. 1447 - 1459 (2007/10/02)
The intramolecular cyclocondensation of 15 cyclic N-(acyloxy)iminium cations containing tethered alkyne and alkene nucleophiles is reported (eqs 5 and 6).This route to heterotricyclic systems was specifically demonstrated with substrates in which the hete
