Published in:European Journal of Organic Chemistry
Language:
English
DOI:
10.1002/ejoc.201800485
ISSN:
1434-193X;
1099-0690
Origination:
Footnote:
Description:
<jats:p>A series of unsymmetrically substituted diastereoisomeric (<jats:italic>R<jats:sub>a</jats:sub>,R</jats:italic>) and (<jats:italic>S<jats:sub>a</jats:sub>,R</jats:italic>) bipyridine <jats:italic>N</jats:italic>,<jats:italic>N′</jats:italic>‐dioxides was synthesized by using oxidative coupling of the corresponding metallated tetrahydroisoquinoline <jats:italic>N</jats:italic>‐oxides in the presence of iodine. The <jats:italic>N</jats:italic>,<jats:italic>N′</jats:italic>‐dioxides contained substituted aryl groups with electron‐donating or electron‐accepting groups in the near vicinity of the <jats:italic>N</jats:italic>,<jats:italic>N′</jats:italic>‐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 % <jats:italic>ee</jats:italic>) with catalyst loadings as low as 0.5 mol‐%. Furthermore, allylation reactions of (<jats:italic>E</jats:italic>)‐3‐iodomethacrylaldehyde were also carried out to give chiral (<jats:italic>E</jats:italic>)‐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 % <jats:italic>ee</jats:italic>) with a catalyst loading of 2.5 mol‐%.</jats:p>