ISSN:
1434-193X
Keywords:
Methylenepyran carbene complexes
;
Lithiation
;
Carbene complexes
;
Tungsten
;
Carbenes
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
---1,2 and 1,6 additions of lithium reagents to γ-methylenepyran Fischer-type carbene complexes are described. The 1,2 adducts obtained from alkynyllithium addition evolve by a 1,3 shift of the W(CO)5 fragment to give allenyltungsten carbonyl intermediates. Reaction with degassed water affords unsaturated carbene complexes indirectly stabilized by a heteroatom. The 1,6 anionic addition products are quenched by H2O at low temperature to give α,δ-unsaturated carbene complexes. On warming, an evolution occurs leading to new pyranylidene carbene complexes.Supporting information for this article is available on the WWW under //http://www.wiley-vch.de/contents/jc_2046/2000/099150_s.pdf or from the author.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
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