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Creators/Authors contains: "Lovstedt, Alex"

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  1. ; ; (, The Journal of Organic Chemistry)
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  2. ; ; (, Acta Crystallographica Section C Structural Chemistry)
    The tetramer of bis(4-di- n -butylaminophenyl)(pyridin-3-yl)borane [systematic name: 2λ 4 ,4λ 4 ,6λ 4 ,8λ 4 -tetrabora-1,3,5,7(1,3)-tetrapyridinacyclooctaphane-1 1 ,3 1 ,5 1 ,7 1 -tetrakis(ylium)], C 132 H 192 B 4 N 12 , was synthesized unexpectedly and crystallized. Its structure contains an unusual 16-membered ring core made up of four (pyridin-3-yl)borane groups. The ring adopts a conformation with pseudo- S 4 symmetry that is very different from the two other reported examples of this ring system. Density functional theory (DFT) computations indicate that the stability of the three reported ring conformations is dependent on the substituents on the B atoms, and that the pseudo- S 4 geometry observed in the bis(4-dibutylaminophenyl)(pyridin-3-yl)borane tetramer becomes significantly more stable when phenyl or 2,6-dimethylphenyl groups are attached to the boron centers. 
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  3. ; ; (, Organometallics)
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  4. ; ; ; (, Journal of Physical Organic Chemistry)
    Abstract Several charge‐containing TADDOL salts were synthesized and used as organocatalysts in asymmetric Diels–Alder and hetero‐Diels–Alder reactions. Their catalytic activity was found to exceed that of a noncharged analog while maintaining or improving upon the enantioselectivity. The enhanced activities of the TADDOL salts enabled them to act as presumed hydrogen bond donor catalysts in the Diels–Alder and hetero‐Diels–Alder reactions of 1,3‐cyclohexadiene with methyl vinyl ketone at 40°C and 2‐phenoxy‐1,3‐butadiene with ethyl glyoxylate at room temperature, respectively. Given the ionic nature of these charge‐activated catalysts, it also proved possible to recycle and reuse the TADDOL without chromatography or the need for a recrystallization. 
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