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Vinyl‐ and Divinylcyclopentadienes by Rhodium‐Catalyzed Condensation of Alkynes with Cross‐Conjugated Amino Metallahexatrienes [= (1‐Amino‐1,3‐butadien‐2‐yl)carbene Complexes] (M = Cr, W)
Author(s) -
Aumann Rudolf,
GöttkerSchnetmann Inigo,
Fröhlich Roland,
Meyer Oliver
Publication year - 1999
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/(sici)1099-0690(199910)1999:10<2545::aid-ejoc2545>3.0.co;2-a
Subject(s) - carbene , chemistry , catalysis , rhodium , medicinal chemistry , conjugated system , transition metal , organic chemistry , polymer chemistry , polymer
We report on the first example of a transition metal‐catalyzed cyclization reaction of a Fischer carbene complex. It comprises the generation of vinyl‐ and divinyl cyclopentadienes under exceedingly mild conditions at 20 °C by condensation of (1‐amino‐1,3‐butadien‐2‐yl)carbene complexes (= cross‐conjugated metallahexatrienes) (CO) 5 MC(OEt)C(CHNR 2 )CR 1 CHR 2 3 (M = Cr, W) with alkynes R 3 C≡CH 4 (R 3 = Ph, cyclohex‐1‐enyl, isopropenyl, methoxymethyl, 1‐trimethylsiloxycyclohex‐1‐yl) in the presence of catalytic amounts of [(COD)RhCl] 2 . The starting compounds 3 are accessible in high yields by addition of enamines ( E )‐R 2 NCHCHR 2 2 to (1‐alkynyl)carbene complexes (CO) 5 MC(OEt)C≡CR 1 1 (M = Cr, W; R 1 = Ph, cyclohex‐1‐enyl).