148081-11-2Relevant academic research and scientific papers
Synthesis of pyrroloindolines through formal [3 + 2]-cycloaddition of indoles with chiral N-2-acetamidoacrylyl oxazolidinones
Smith, Isaac T.,Neeley, Jared B.,Brinley, Tanner D.,Fullmer, Peter R.,Andrus, Merritt B.
, (2020)
Chiral N-2-acetamidoacrylyl oxazolidinones were produced and reacted with indoles under Lewis acid conditions to generate hexahydropyrrolo[2,3-b]indole products in a formal [3 + 2] cycloaddition process. Optimal conditions included the use of tin(IV) chloride in methylene chloride at 0 °C. Pyrroloindoline products were obtained from various indoles with shorter reaction times (12 hr) up to 91% yield with high, >20:1 exo selectivity. A mechanism involving reversible conjugate addition followed by an enamine lone-pair-iminium capture, tautomerization, and tin-enolate protonation accounts for the selectivity. The method enables selective applications to pyrroloindoline targets and further refinement with chiral catalysts.
Asymmetric 1,3-dipolar cycloaddition reactions of nitrones with (S)-(-)-4-benzyl-N-methacryloyl-2-oxazolidinone
Tyrrell, Elizabeth,Allen, Jackie,Jones, Keith,Beauchet, Romain
, p. 2393 - 2399 (2005)
The [3+2]-nitrone-mediated cycloaddition reaction of (S)-(-)-4-benzyl-N- methacryloyl-2-oxazolidinone has been applied to the synthesis of highly substituted isoxazolidines with controlled stereochemistry. The absolute configuration of the major diastereo
Copper-catalysed domino silylative aldol reaction leading to stereocontrolled chiral quaternary carbons
Welle, Alexandre,Petrignet, Julien,Tinant, Bernard,Wouters, Johan,Riant, Olivier
supporting information; experimental part, p. 10980 - 10983 (2010/11/21)
(Chemical Equation Presented) Asymmetric aldol reaction: A domino silylation-aldol reaction between enoyloxazolidinones and various aldehydes has been developed (see scheme). The process catalysed by a copper complex in the presence of a borosilane led to high diastereoselectivities. Yields between 59 and 90 % and d.r. values between 78:22 to 95:5 were obtained. When methacryloyloxazolidinones were used, a controlled chiral quaternary carbon was generated. BPin=4,4,5,5-tetramethyl-1,3,2dioxaborolan-2-yl.
Sulfinyl moiety as an internal nucleophile. 1. Efficient stereoselective synthesis of fragment A of cryptophycin 3
Raghavan, Sadagopan,Tony
, p. 5002 - 5005 (2007/10/03)
A novel, efficient, and stereoselective synthesis of fragment A of cryptophycin 3 is disclosed. The key step involves the regio- and stereoselective transformation of an unsaturated ester to a bromohydrin via anchimeric assistance by the sulfinyl group.
Palladium(II)-Catalyzed Asymmetric Acetalization of Alkenes
Hosokawa, Takahiro,Yamanaka, Toshio,Itotani, Motohiro,Murahashi, Shun-Ichi
, p. 6159 - 6167 (2007/10/03)
The terminal olefinic carbon of N-methaacryloyl-2-oxazolidinones is smoothly acetalized by alcohols in the presence of PdCl2 catalyst.The use of 4(S)-isopropyl-, phenyl-, and tert-butyl-2-oxazolidinones as the chiral auxiliary resulted in the formation of the corresponding (2'S)-acetals in 61, 80, and 95percent de, respectively.Reductive removal of the auxiliary with LiAlH4 followed by deacetalization produced (R)-3-hydroxy-2-methylpropanal.The enantiomer of this compound, derived from 4(R)-substituted oxazolidinones, served as a building block for synthesizing a 1β-methylcarbapenem precursor in high enantiomeric excess.In the acetalization of 3',3'-dideuteriated methacryloyl-4-isopropyloxazolidinone with MeOH, one D-atom on the terminal olefinic carbon stereoselectively migrated to the chiral center in the product acetal.On the basis of this 1,2-hydride migration and the conformational preference of the methacryloyl moiety, the reaction pathway and the mechanism of the diastereoselection are discussed.
