Petasis reagent

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Petasis reagent

General
Systematic name	bis(n⁵-2,4-cyclopentadien-1-yl) dimethyl-titanium
Other names	dimethyl titanocene
Molecular formula	C₁₂H₁₆Ti
SMILES	C[Ti](C)(C)c.c1cccc1.c2cccc2
Molar mass	208.13 g/mol
Appearance	yellow solution in toluene
CAS number	[ 1271-66-5]
Properties
Solubility in water	slowly hydrolyzes
Other solvents	soluble in toluene
Hazards
MSDS	External MSDS
Main hazards	Irritant, incompatible with water and oxidizing agents
NFPA 704
Flash point	?°C
R/S statement	R: ? S: ?
RTECS number	?
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related compounds	?
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

The Petasis reagent (not to be confused with the Petasis reaction) is dimethyl titanocene, Cp₂TiMe₂, readily prepared by the reaction of methyl magnesium chloride or methyllithium with Titanocene dichloride. It is used for transforming carbonyl groups to terminal alkenes, much like the Tebbe reagent or Wittig reaction. Unlike the Wittig reaction, the Petasis reagent can react with a wide range of carbonyls, including aldehydes, ketones and esters. The Petasis reagent is also more air stable than the Tebbe reagent, and can be isolated as a pure solid, or used directly as a solution in toluene-THF.

The active olefinating reagent, Cp₂TiCH₂, is prepared by heating the petasis reagent in toluene or THF to 60 °C.

[edit] References

Payack, J. F.; Hughes, D. L.; Cai, D.; Cottrell, I. F.; Verhoeven, T. R. Dimethyltitanocene Organic Syntheses, Coll. Vol. 10, p.355 (2004); Vol. 79, p.19 (2002).
Petasis, N.A.; Bzowej, E.I. "Titanium-Mediated Carbonyl Olefinations. 1. Methylenations of Carbonyl Compounds with Dimethyltitanocene" J. Am. Chem. Soc. 1990, 112, 6392-6394. (DOI:10.1021/ja00173a035)