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Substrate‐Controlled Aza‐Ene/Prins Cyclization for the Synthesis of Dihydroquinoline and Oxocene Derivatives
Author(s) -
Chandrashekhar Rapelli,
Sridhar Balasubramanian,
Reddy Basi V. Subba
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201900095
Subject(s) - prins reaction , tetrahydropyran , ene reaction , chemistry , aldehyde , catalysis , substituent , substrate (aquarium) , ring (chemistry) , stereochemistry , organic chemistry , medicinal chemistry , oceanography , geology
A substituent controlled aza‐ene/Prins cyclization strategy has been developed for the one‐pot synthesis of dihydroquinoline tethered tetrahydropyran derivatives from ortho ‐aminoaryl alkenols and aromatic aldehydes using 30 mol% TMSOTf at 60 °C. The reaction proceeds through a sequential aza‐ene and Prins cyclization. In the case of nitro and cyano substituted aromatic aldehydes, eight‐membered oxocene derivatives were obtained under similar conditions. This is the first report on the introduction of tetrahydropyran ring at 4th position of dihydroquinoline from ortho ‐aminoaryl alkenol and aromatic aldehyde in the presence of an acid catalyst. A catalytic amount of TMSOTf facilitates aza‐ene and Prins cyclizations sequentially in a single‐step.