Trimethylsilyl indene

Analogous to the allylsilane cyclizations, alkynylsilanes can also be used to synthesize 1,2-fused bicyclic compounds. The intramolecular addition of 4-[5-(trimethylsilyl)-3-pentynyl]-2-cyclo-hexenone proceeded smoothly in the presence of various Lewis acids, yielding functionalized cw-fused octahydro-5/f-inden-5-ones containing the synthetically useful terminal allene unit45. 

C6H7NO3S2 138890-97-8) see Brinzolamide dihydro-2-imino-5-methoxy-4,6(1/1,5/I)-pyrimidinedione (C,H7N,0, 89280-05-7) see Sulfametoxydiazine 23-dihydro-2-(l-iminopropyl)-2-[(trimethylsilyl)oxy ]- //-indene... 

Thermolysis of 44 produced products derived from the Myers-Saito cyclization reaction. However, when 43 having a trimethylsilyl substituent at the acetylenic terminus was subjected to heating in the presence of 1,4-CHD at 70 °C for 3 h, the 1H-cyclobut[a]indene 46 was produced. A reaction mechanism involving an initial Schmittel cyclization to generate the benzofulvene biradical 45 followed by an intramolecular radical-radical coupling was proposed to account for the formation of the formal [2 + 2]-cycloaddition product 46. 

A GENERAL [3+2] ANflULATION CIS-4-EX0-IS0PR0PENYL-1,9-DlNETHYL-8-(TRIMETHYLSILYL)BICYCLO[4.3.0]NON-8-EN-2-ONE (4H-Inden-4-one, 1,3a,5,6,7,7a-hexahyd ro-3,3a-dimethyl-6-(1-methyletheny1)-2-(tnmethylsilyl)-, (3act,6a,7aa)-)... 

While the preparations of l-(trimethylsilyl)indene and l-(trimethylstannyl)-indene have been reported,4 there are no available preparations of l-(tributyl-stannyl)indene. We chose the tributyl analog because of the decreased toxicity of tributyltin reagents vs. trimethyltin reagents.5 A preparation for the synthesis of Mg(C9H7)2, another indenyl transfer agent, has appeared in Inorganic Syntheses.6... 

Tributylstannylindene is a clear, pale yellow liquid with a density of 1.070 g/mL. As with l-(trimethylsilyl)indene, l-(tributylstannyl)indene is best stored in the dark under an atmosphere of argon (or nitrogen). 

All reactions and manipulations should be performed under an atmosphere of nitrogen (or argon), using either a dry box or standard Schlenk techniques.7 Neat l-(trimethylsilyl)indene (4.7 mL, 22.8 mmol) is added to a room-temperature suspension of HfCl4 (7.29 g, 22.8 mmol) in toluene... 

The relatively strong Bronsted acidity of cyclopentadienes, indenes, and fluorenes, permits the formation of alkali metal compounds of the conjugate bases of these organic molecules by direct reaction with the metal. The effect of substitnents on the rate of formation of 9-R-fluorenylhthium componnds in THE solution and on the degree of ion pairing in solutions of these species has been determined. Potassinm derivatives are commonly prepared by the reaction of the cyclopentadiene with potassium bis(trimethylsilyl)amide. Eluorenyl and indenyl compounds with the heavier alkah metals, Rb and Cs, are also prepared by reaction with the metal bis(trimethylsilyl)amide. The cyclopentadienyl ring in alkali metal compounds can also be coordinated to other metals. ... 

The reaction of dichlorocarbene with aromatic compounds, with a few exceptions, lacks preparative value the adducts rearrange undergoing addition of another molecule of carbene and the final yield of complex product mixture rarely exceeds more than a few percent. Of synthetic importance are the reactions with indenes, phenanthrene (its 9-substituted derivatives 9-ethoxy-,9-trimethylsilyl-, " 9-arylthio-, 9-arylseleno- ), pyrene and various alkyl-naphthalenes. 120 Reactions with aromatic compounds are discussed in Houben-Weyl, Vol. E19b, pp 1551-1553. 

Bis(trimethylsilyl)fluorenylmethyl, 713 9-(2-Sulfo)fluorenylmethyl, 714 9-(2,7-Dibromo)fluorenylmethyl, 714 17-Tetrabenzo[a,c,g,(]fluorenylmethyl, 714 2-Chloro-3-indenylmethyl, 715 Benz[/]inden-3-ylmethyl, 715... 

In the hydroalumination of cyclic olefins with i-Bu2AlH the cis-addition in donor solvents is kinetically controlled . For indenes, polar effects are noticable, whereas steric effects are most important for 1-substituted acenaphtenes . The regiochemistry of the addition is controlled by steric effects except for trimethylsilyl substituents . The... 

A similar procedure is followed for the reaction of indenyllithium with trimethylchlorosilane (a 100% molar excess of Me3SiCl is used). 1-(Trimethylsilyl)indene, b.p. 105 °C/12 mmHg, nD(20) 1.5422, is obtained in 70% by careful fractional distillation. The small fraction with b.p. 106-115 °C/12 mmHg contains 2Q% of 3-(trimethylsilyl)indene and some of a bis(trimethylsilyl) derivative. 

A soln. of cyclopentadiene in THF treated with a soln. of K-bis(trimethylsilyl)amide in toluene at 0°, the grey slurry cooled to —78°, HMPA added, after 10 min a pre-cooled soln. of /cr/-butyldimethylsilyl chloride in THF added, followed within 2 min by propionyl chloride in the same solvent, slowly warmed to room temp, for 10 min, and quenched with satd. NH4CI 6-[/cr/-butyldimethylsilyl)oxy]-6-ethylful-vene. Y 92%. F.e. and 6-acoxyfulvenes s. J.I. McLoughlin, R.D. Little, J. Org. Chem. 53, 3624-6 (1988) indene and fluorene analogs cf. S.N. Naik et al., Synth. Commun. 18, 625-32 (1988). 

Takeuchi, R. Yasue, H. (1993) Rhodium complex-catalyzed desilylative cyclocarbonyla-tion of l-aryl-2-(trimethylsilyl)acetylenes - a new route to 2,3-dihydro-1 -inden-l-ones, J. Org. Chem., 58, 5386-92. 

Reaction of bis(cyclopentadienyl)diphenyltitanium(iv) with acetylenes affords a general route to titana-indenes. The products from the reactions with phenyl-(trimethylsilyl)ethyne and bis(pentafluorophenyl)ethyne were both characterized by single crystal Z-ray studies, and the structure of the former is shown in (6). The structure is drawn with the one double bond, because, unlike metallocyclo-pentadienes in general, the Ci—Ca bond in (6) is significantly shorter than C3—C4, which is typically aromatic. The two Ti—C bonds in (6) are similar in length but the Ti—Cx bond length in the pentafluorophenyl compound is longer, which the authors attribute to steric factors. ... 

The reaction between [RuGl3 / (iV,iV,A0-tmtacn ] (tmtacn = l,4,7-trimethyl-l,4,7-triazacyclononane) and 3equiv. of Ag[OTf generates an uncharacterized green species which upon treatment with l-(trimethylsilyl)cyclopentadiene and l-(trimethylsilyl)indene, in the presence of zinc dust and [NH4][PF6], yields [RuGp Ac (iV,iV,iV)-tmtacn ][PF6] and [Ru(77 -G9H7) / (A,A,A0-tmtacn ][PF6], respectively. 

Hafner synthesized tetra-ferf-butylfulvalene 13 from di-terl-butylcyclopenta diene, as shown in Scheme 6.52a [5]. The method involves oxidative coupling of the corresponding CP anion with iodine. Unexpectedly, subsequent treatment of indene with n-butyllithium and trimethylsilyl chloride (TMSCl) afford diben-zofulvalene 199 as a stable bright red solid in low yield together with sUylated indenes (Scheme 6.52b) [123]. 

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