Chiral Unsymmetrically Substituted Bipyridine N,N-Dioxides as Catalysts for the Allylation of Aldehydes

0495570 - ÚOCHB 2019 RIV DE eng J - Článek v odborném periodiku
Ulč, J. - Nečas, D. - Koukal, P. - Havlíček, V. - Tošner, Z. - Hybelbauerová, S. - Kotora, Martin
Chiral Unsymmetrically Substituted Bipyridine N,N-Dioxides as Catalysts for the Allylation of Aldehydes.
European Journal of Organic Chemistry. Roč. 2018, č. 37 (2018), s. 5109-5116. ISSN 1434-193X. E-ISSN 1099-0690
Institucionální podpora: RVO:61388963
Klíčová slova: organocatalysis * asymmetric synthesis * asymmetric catalysis * allylation * aldehydes * catalyst design
Obor OECD: Organic chemistry
Impakt faktor: 3.029, rok: 2018

A series of unsymmetrically substituted diastereoisomeric (R-a,R) and (S-a,R) bipyridine N,N-dioxides was synthesized by using oxidative coupling of the corresponding metallated tetrahydroisoquinoline N-oxides in the presence of iodine. The N,N-dioxides contained substituted aryl groups with electron-donating or electron-accepting groups in the near vicinity of the N,N-dioxide moiety. Their catalytic activity was tested in a series of reactions of allyltrichlorosilane with various substituted benzaldehydes, thiophenecarbaldehyde, and cinnamaldehyde. The reactions proceeded with high enantioselectivities (up to 98% ee) with catalyst loadings as low as 0.5 mol-%. Furthermore, allylation reactions of (E)-3-iodomethacrylaldehyde were also carried out to give chiral (E)-1-iodo-2-methylpenta-1,4-dien-3-ol, a convenient building block for the synthesis of natural products. The allylations proceeded with high enantioselectivities (up to ca. 99% ee) with a catalyst loading of 2.5 mol-%.
Trvalý link: http://hdl.handle.net/11104/0288519