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Stereoselective Reductive Opening of 2,3‐Benzofuran − A Two‐Step Synthesis of 2 H ‐Chromenes Including Deoxycordiachromene
Author(s) -
Yus Miguel,
Foubelo Francisco,
Ferrández José V.
Publication year - 2001
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 - 10.1002/1099-0690(200108)2001:15<2809::aid-ejoc2809>3.0.co;2-t
Subject(s) - chemistry , benzofuran , stereoselectivity , stereochemistry , combinatorial chemistry , organic chemistry , catalysis
The reaction of 2,3‐benzofuran ( 1 ) with lithium and a catalytic amount of 4,4′‐di‐ tert ‐butylbiphenyl (TDBB, 5 mol %) in THF at 0 °C leads to the stereoselective ring opening of the heterocycle, yielding the ( Z )‐organolithium derivatives ( 2 ) which, by reaction with different electrophiles [H 2 O, D 2 O, t BuCHO, PhCHO, Ph(CH 2 ) 2 CHO, Me 2 CO, n PrCOMe, PhCOMe, (CH 2 ) 4 CO] at −78 °C and final hydrolysis with water, give the expected ( Z )‐products 3 . Cyclisation of the products obtained by reaction with carbonyl compounds under acidic conditions affords the expected substituted 2 H ‐chromenes 4 , including deoxycordiachromene 4j .