27436-98-2Relevant articles and documents
Preparation of acylpentacarbonylchromate salts and alkoxycarbene pentacarbonyl complexes of chromium employing the pentacarbonylchromate dianion ([Cr(CO)5]2-)
Semmelhack,Lee
, p. 1839 - 1844 (2008/10/08)
The in situ generated lithium and sodium salts of [Cr(CO)5]2- (3) react rapidly and cleanly with a variety of aryl and alkyl acid chlorides at -78°C in THF to provide solutions of the corresponding acylpentacarbonylchromate salts M′[RC(O)Cr(CO)5] (M′[1], M′ = Li, Na). Subsequent O-methylation of 1 produces Fischer-type alkoxycarbene complexes in yields competitive with established methodologies. This two-step procedure has enabled the preparation of arylmethoxycarbene complexes such as (CO)5Cr=C(OMe)-{2,5-(OAc)2C6H3} (2g) which are otherwise inaccessible by the standard Fischer synthesis. Alkoxycarbene complexes of molybdenum and tungsten may be prepared analogously from [Mo(CO)5]2- and [W(CO)5]2-.
