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A One‐Pot Three‐Step Synthesis of Z ‐Trisubstituted Olefins from Arylalkynes and Their Cyclization into 4‐Aryl‐2 H ‐chromenes
Author(s) -
Rasolofonjatovo Evelia,
Tréguier Bret,
Provot Olivier,
Hamze Abdallah,
Brion JeanDaniel,
Alami Mouâd
Publication year - 2012
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.201101735
Subject(s) - aryl , chemistry , substituent , halide , catalysis , palladium , combinatorial chemistry , medicinal chemistry , organic chemistry , alkyl
Rapid and versatile access to ( Z )‐trisubstituted olefins 2 and their cyclization into 4‐aryl‐2 H ‐chromenes 1 starting fromarylalkynes 3 is described. In a one‐pot fashion, alkynes 3 were first hydrated, then transformed into N ‐tosylhydrazones, and finally coupled with ortho ‐substituted aryl halides under palladium catalysis to give trisubstituted olefins 2 in good yields and very high to total Z selectivity. 1,1‐Diarylolefins 2 having an ortho ‐OMOM (methoxymethoxy) substituent underwent rapid cyclization in the presence of p ‐toluensulfonic acid to give a variety of 4‐aryl‐2 H ‐chromenes in good to excellent yields. This methodology was also successfully applied to the preparation of 5‐aryl‐2,3‐dihydrobenzo[ b ]oxepine 4 from the required arylbutynol 3b .