18069-22-2Relevant academic research and scientific papers
Enantioselective Acyloin Rearrangement of Acyclic Aldehydes Catalyzed by Chiral Oxazaborolidinium Ion
Cho, Soo Min,Lee, Si Yeon,Ryu, Do Hyun
, p. 1516 - 1520 (2021/03/03)
A catalytic enantioselective acyloin rearrangement of acyclic aldehydes to synthesize highly optically active acyloin derivatives is described. In the presence of a chiral oxazaborolidinium ion catalyst, the reaction provided chiral α-hydroxy aryl ketones in high yield (up to 95%) and enantioselectivity (up to 98% ee). In addition, the enantioselective acyloin rearrangement of α,α-dialkyl-α-siloxy aldehydes produced chiral α-siloxy alkyl ketones in high yield (up to 92%) with good enantioselectivity (up to 89% ee).
The attempted stereoselective synthesis of chiral 2,2′-biindoline
Gresser, Mary J.,Wales, Steven M.,Keller, Paul A.
scheme or table, p. 6965 - 6976 (2010/09/18)
The attempted first stereoselective synthesis of 2,2′-biindoline using a metathesis-Sharpless asymmetric dihydroxylation strategy results in the synthesis of the heterocycle in poor to modest stereoselectivity. Attempts to improve the ee by varying the he
Synthesis and reactivity of enantiomerically enriched thiiranium ions
Denmark, Scott E.,Vogler, Thomas
supporting information; experimental part, p. 11737 - 11745 (2010/06/12)
Enantiomerically enriched thiiranium ion 5 has been prepared by silverassisted ionization of chloro sulfide 4 at -20°C. This thiiranium ion is configurationally stable in solution up to room temperature as demonstrated by the stereospecific capture of the ion by various oxygen- and nitrogen-based nucleophiles. Both isolated olefins and weak Lewis bases can promote the racemization of 5 but these processes can also be suppressed at low temperature. Capture of 5 by methanol is faster than the racemization processes.
Concise assembly of the polycyclic frameworks associated with the hapalindole and fischerindole alkaloids
Banwell, Martin G.,Ma, Xinghua,Taylor, Rebecca M.,Willis, Anthony C.
, p. 4959 - 4961 (2007/10/03)
Reaction of N-methylindole (4) with 6,6-dibromobicyclo[3.1.0]hexane (5) in the presence of silver tetrafluoroborate affords conjugate 7 in 67% yield. This product can be readily elaborated to compounds 12b and 13b which embody the polycyclic frameworks as
Modular asymmetric synthesis of 1,2-diols by single-pot allene diboration/hydroboration/cross-coupling
Pelz, Nicholas F.,Morken, James P.
, p. 4557 - 4559 (2007/10/03)
Chiral allyl vinyl boronates are generated by catalytic enantioselective diboration of prochiral allenes. They may then be reacted, in situ, with a hydroborating reagent to form a novel triboron intermediate. The least hindered and most reactive C-B bond
Enantioselective addition of organolithium reagents to imines mediated by c2-symmetric bis(aziridine) ligands
Andersson, Pher G.,Johansson, Fredrik,Tanner, David
, p. 11549 - 11566 (2007/10/03)
The C2-symmetric bis(aziridine) ligands 1-5 have been screened in the enantioselective addition of organolithium reagents to imines. Ligand 1 (used in stoichiometric amounts) was found to be superior in terms of chemical yield and enantioselect
Heterodiene cycloadditoins of C2 symmetric 4,5-disubstituted ketene acetals: the nett asymmetric conjugate addition of recyclable acetic ester enolate equivalents to an activated enone
Wallace, Timothy W.,Wardell, Ian,Li, Ke-Dong,Leeming, Peter,Redhouse, Alan D.,Challand, S. Richard
, p. 2293 - 2308 (2007/10/02)
Heterodiene cycloadditions of 3-formylchromone 2 to a series of ketene acetals 1 derived from C2 symmetric 1,2-diarylethane-1,2-diols are diastereoselective.From (S,S)-1,2-di(o-tolyl)ethane-1,2-diol 6c the major cycloadduct 3c was isolated by crystallization and transformed by acid-catalysed methanolysis into (S)-methyl 4-oxo-3,4-dihydro-2H-1-benzopyran-2-ylacetate 5, together with the original 1,2-diol 6c which could be recycled.The structures of two cyclic carbonates 22a and 22c were determined by X-ray diffraction and used as models in seeking a mechanistic rationale for the stereoselective cycloadditions of the analogous ketene acetals 1a and 1c.
