| 1. |
- Borg, Tessie, et al.
(författare)
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Diastereoselective Nucleophilic Addition to Aldehydes with Polar alpha- and alpha,beta-Substituents
- 2011
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Ingår i: Advanced Synthesis and Catalysis. - : Wiley. - 1615-4150 .- 1615-4169. ; 353:11-12, s. 2022-2036
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Tidskriftsartikel (refereegranskat)abstract
- The stereoselectivities obtained in Lewis acid-promoted Mukaiyama aldol additions and Sakurai allylations of mono-, and syn- and anti-disubstituted aldehydes possessing various polar alpha- and beta-substituents under non-chelating conditions are presented. The stereochemical outcome in the nucleophilic addition to alpha-substituted aldehydes containing an alpha-benzyloxy, alpha-fluoro or alpha-sulfonamide substituent are accurately predicted by current stereoinduction models. In contrast, the selectivitites obtained from addition of sterically demanding nucleophiles to alpha-chloro-substituted aldehydes cannot be rationalized by the same models and an alternative is discussed. The stereochemichal outcome in the additions to alpha, beta-disubstituted aldehydes is more complex and cannot be predicted using current models.
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| 2. |
- Mohiti, Maziar, et al.
(författare)
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Regio- and Enantioselective Synthesis of 1,2-Diamines by Formal Hydroamination of Enamines : Scope, Mechanism, and Asymmetric Synthesis of Orthogonally Protected Bis-Piperazines as a Privileged Scaffold
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Ingår i: Chemistry - A European Journal. - 0947-6539.
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Tidskriftsartikel (refereegranskat)abstract
- We have previously reported the first formal hydroamination of enamines for the synthesis of chiral 1,2-diamines. Here, we describe: (i) the discovery, optimization, and substrate expansion of this reaction; (ii) a novel and straightforward protocol for the “click-type” synthesis of enamines in quantitative yield utilizing sodium sulfate in a dual role as an ancillary and dehydrating agent without the need for workup or purification; (iii) the application of this methodology to the first enantioselective synthesis of orthogonally protected 1,1′-(1-(4-fluorophenyl)ethane-1,2-diyl) piperazines, a scaffold for rapid lead optimization in drug discovery; (iv) a computational investigation into the mechanism and rationalization of the enantioselectivities of the reaction.
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