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Sterically Congested Chiral 7,8‐Dioxa[6]helicene and Its Dihydro Analogues: Synthesis, Regioselective Functionalization, and Unexpected Domino Prins Reaction
Author(s) -
Hasan Mohammed,
Pandey Anita D.,
Khose Vaibhav N.,
Mirgane Nitin A.,
Karnik Anil V.
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201500327
Subject(s) - helicene , regioselectivity , chemistry , steric effects , enantiomer , domino , diol , stereochemistry , surface modification , total synthesis , combinatorial chemistry , organic chemistry , molecule , catalysis
A C 2 ‐symmetric 7,8‐dioxa[6]helicene‐2,13‐diol was synthesized from readily available 2,7‐dihydroxynaphthalene on a gram scale. A high‐yielding synthetic strategy for the regioselective hydroxymethylation at the sterically most hindered C1 position of diol analogues was investigated. The dioxa[6]helicene backbone with configurationally stable helical enantiomers was synthesized, and these enantiomers were separated by HPLC on a chiral stationary phase. We also observed an unexpected domino Prins reaction. This is the first report of a domino Prins reaction occurring on a helicene. Along with the high‐yielding regioselective functionalization of dioxa[6]helicene analogues, the synthesis of a few cis ‐7a,14c‐dihydro‐functionalized helicenoid diols substituted at the sterically most hindered C1 and C14 positions in their racemic forms was explored.