ISSN:
0009-2940
Keywords:
Tungsten complexes
;
Carbonyl dimerization
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Organomolybdenum and Organotungsten Reagents, V[1]. - On the Additive, Reductive Carbonyl Dimerization (ARCD Reaction)Reagents of the type R4(PrO)4(μ-PrO)2W2 (3; R = Me, Et, Pr, Bu, sBu, iBu, Hex, Me3SiCH2, Ph) prepared in situ by the action of organolithium or Grignard compounds on (PrO)4(μ-PrO)2-W2Cl4 (2), react with aromatic aldehydes or ketones and with the α,β-unsaturated ketone benzylidene acetone in a novel reaction, called the ARCD reaction, to give products 4 of the type RRRC - CRRR with mostly good yields. In the case of benzylidene acetone and furfural besides the ARCD products the rearranged products 27 and 29 are formed. With the reagent Ph4(PrO)4(μ-PrO)2W2 (3b) ARCD reactions are also possible in moderate yields with aliphatic aldehydes and ketones. The more closely investigated reagent Me4(PrO)4(μ-PrO)2W2 (3a; decomposition at about - 45C) tolerates the aromatic bound functional groups Cl, F, OH, OMe, and NMe2 in the substrates, but not the NO2 and CO2Et substituents. It reacts with PhCOX (X = OEt, Cl, OCOPh) via acetophenone to give PhCMe2 - CMe2Ph. - For the ARCD reactions a radical mechanism (Scheme 7) is postulated.
Additional Material:
5 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19931260919
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