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Benzolactone und Benzocarbocyclen durch Ringerweiterung von Benzocycloalkenonen
Author(s) -
Benkert Erwin,
Hesse Manfred
Publication year - 1987
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19870700823
Subject(s) - chemistry , bicyclic molecule , methyl vinyl ketone , adduct , ketone , ring (chemistry) , yield (engineering) , primary (astronomy) , michael reaction , medicinal chemistry , polymer chemistry , organic chemistry , catalysis , materials science , physics , astronomy , metallurgy
Benzolactones and Benzocarbocycles by Ring Enlargement of Benzocycloalkenone Derivatives The Michael adducts 5–8 of benzonitrocycloalkenones 1–4 and acrylaldehyde are converted with (CH 3 ) 2 Ti(iPrO) 2 or NaCNBH 3 to secondary and primary alcohols, 9–12 and 13–16 , respectively. These alcohols react under basic conditions to form ring‐enlarged benzonitrolactones and benzooxolactones ( Scheme 1 ). The configuration of the bicyclic intermediates in this enlargement step is discussed. The Michael reactions of benzonitrocycloalkenones with methyl vinyl ketone lead to oxoalkyl‐benzonitrocycloalkenones 35‐‐38 . These products rearrange in the presence of t‐BuOK to yield benzonitrocycloalkenones 42 , 44 , and 46 , enlarged by two C‐atoms, or tricyclic hydroxy compounds 39 , 41 , 43 , and 45 ( Scheme 4 ).
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