Brom und Acetyldiphenylthioharnstoff in Chloroformlösung

Hugershoff, A.; König, Wolf

doi:10.1002/cber.190103402287

Cited by 2 publications

(1 citation statement)

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“…[18,19] However,the corresponding route to the isoselenourea 1-Se gave low yields, [19] necessitating the development of anew route to 1-Se.Inaone-pot process, 2 [18a] was added to phenyl isoselenocyanate (3)t og enerate selenourea 4,w hich was then cyclized to give 5 in what is the first reported seleno-Hugerschoff reaction (Figure 2B). [20,21] Adapting the previously reported approach, in situ addition of NEt 3 and MsCl followed by gentle heating affected cyclization to give isoselenourea 1-Se in good yield. Thereaction could be performed on agram scale giving 1.1 g (3.1 mmol) of 1-Se in 64 %yield from 2 and 3.…”

Section: Resultsmentioning

confidence: 95%

The Importance of 1,5‐Oxygen⋅⋅⋅Chalcogen Interactions in Enantioselective Isochalcogenourea Catalysis

et al. 2020

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The importance of 1,5‐O⋅⋅⋅chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N‐acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5‐O⋅⋅⋅Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including nitronate conjugate addition and formal [4+2] cycloadditions. A gram‐scale synthesis of the most active selenium analogue was developed using a previously unreported seleno‐Hugerschoff reaction, allowing the challenging kinetic resolutions of tertiary alcohols to be performed at 500 ppm catalyst loading. Density functional theory (DFT) and natural bond orbital (NBO) calculations support the role of orbital delocalization (occurring by intramolecular chalcogen bonding) in determining the conformation, equilibrium population, and reactivity of N‐acylated intermediates.

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Section: Resultsmentioning

confidence: 95%