ISSN:
0009-2940
Keywords:
Carbonylolefination
;
Chemoselectivity
;
μ-Methylene complexes
;
Molybdenum reagent
;
Tungsten reagent
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Organomolybdenum and Organotungsten Reagents, IV. - About the Chemoselectivity of the Carbonylmethylenating Reagent from 2 MoOCl3(THF)2 and 4 CH3LiFrom a series of carbonylolefinating Mo complexes the reagent “3”, obtained by low-temperature methylation of two equivalents of MoOCl3(THF)2 with four equivalents of methyllithium and warming up, is especially favourable for chemoselective carbonylolefination reactions. It is readily accessible, reacts at low temperatures, exhibits high aldehydeversus-ketone selectivity (Tables 1, 2; Scheme 2), high cheleselectivity (preference of a keto group in the α- or β- position to a hydroxy group before an isolated keto group: Table 4; Scheme 3), and in some cases anticheleselectivity (Table 6). It is nonbasic and tolerates hydroxy groups (even water in the solvent) as well as acyl chloride groups (Table 8). - The chemoselectivity of 3 is compared in several cases with other carbonylolefinating reagents.
Additional Material:
8 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19931260115
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