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Intramolecular Heck Reaction for the Synthesis of Isochromanes under Ambient and High pressure
Author(s) -
Tietze Lutz F.,
Burkhardt Olaf,
Henrich Marielouise
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719970516
Subject(s) - chemistry , intramolecular force , regioselectivity , alkene , iodide , substituent , heck reaction , high pressure , medicinal chemistry , selectivity , ambient pressure , organic chemistry , palladium , catalysis , physics , engineering physics , engineering , thermodynamics
The iodoarenes 9 and 10 , bearing ( E )‐ and ( Z )‐alkene moieties, respectively, easily prepared by alkylation of the corresponding alcohols 7a–c and 8a–c with 2 iodobenzyl iodide, undergo intramolecular Heck reactions to give the isochromanes 12–15a–c in good yields. The selectivity of the reaction depends on the size of the substituent R in 9 and 10 ; increasing bulkiness of R leads to a decrease in diastereoselectivity and an increase in regioselectivity. High‐pressure experiments confirm the proposed mechanism and show that bromoarenes such as 11 , which tend to be unreactive at ambient pressure, give good results when the cyclisation is performed under high pressure.