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Synthesis of 3,4‐Dihydroisoquinolin‐1‐ones from N ‐Boc‐(β‐Arylethyl)carbamates via Isocyanate Intermediates
Author(s) -
In Jinkyung,
Hwang Soonho,
Kim Changhun,
Seo Jae Hong,
Kim Sanghee
Publication year - 2013
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.201201408
Subject(s) - chemistry , regioselectivity , isocyanate , ring (chemistry) , nucleophile , friedel–crafts reaction , lewis acids and bases , thiophene , aryl , medicinal chemistry , organic chemistry , catalysis , polyurethane , alkyl
Mild reaction conditions for the regioselective synthesis of isoquinolin‐1‐ones and related fused‐ring heterocycles from N ‐Boc‐protected (β‐arylethyl)carbamates are described. The reactions involved the use of Tf 2 O and 2‐chloropyridine and isocyanates are likely to be key intermediates. The method was extended to substrates bearing less nucleophilic aryl moieties by using Lewis acid additives, such as BF 3 · Et 2 O, to enhance the Friedel–Crafts‐type cyclization of the isocyanate intermediates. This method allowed the synthesis of various substituted isoquinolin‐1‐ones, β‐carbolines, thiophene‐fused ring systems and tetrahydrobenzoazepin‐1‐ones in good yields and with high regioselectivities.