5689-12-3Relevant articles and documents
Carbenoid-mediated nucleophilic "hydrolysis" of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants
Knorr, Rudolf,Menke, Thomas,Freudenreich, Johannes,Pires, Claudio
, p. 307 - 315 (2014/03/21)
2-(Dichloromethylidene)-1,1,3,3-tetramethylindane was " hydrolyzed" by solid KOH in DMSO as the solvent at ≥100 °C through an initial chlorine particle transfer to give a Cl,K-carbenoid. This short-lived intermediate disclosed its occurrence through a reversible proton transfer which competed with an oxygen transfer from DMSO that created dimethyl sulfide. The presumably resultant transitory ketene incorporated KOH to afford the potassium salt of 1,1,3,3-tetramethylindan-2-carboxylic acid (the product of a formal hydrolysis). The lithium salt of this key acid is able to acylate aryllithium compounds, furnishing one-sidedly overcrowded ketones along with the corresponding tertiary alcohols. The latter side-products (ca. 10%) were formed against a substantially increasing repulsive resistance, as testified through the diminished rotational mobility of their aryl groups. As a less troublesome further side-product, the dianion of the above key acid was recognized through carboxylation which afforded 1,1,3,3-tetramethylindan- 2,2-dicarboxylic acid. Brominative deoxygenation of the ketones furnished two one-sidedly overcrowded bromoalkenes. Some presently relevant properties of the above Cl,K-carbenoid are provided in Supporting Information File 1.
Lewis acid catalyzed reactions of thioketones with 1,2-epoxycyclohexane and 1,2-epoxycyclopentane
Blagoev, Milen,Linden, Anthony,Heimgartner, Heinz
, p. 2316 - 2335 (2007/10/03)
Non-enolizable thioketones and 1,2-epoxycyeloalkanes undergo a Lewis acid catalyzed addition reaction to give 1,3-oxathiolanes. Appropriate reaction conditions are CH2Cl2 as the solvent BF3. Et2O as the Lewis acid, and a temperature between -78°and r.t. Under the reaction conditions, the 1,3-oxathiolanes are only moderately stable. They decompose to yield the corresponding epithiocycloalkane and ketone. In general, 1,3-dithiolanes are isolated as minor products or, after prolonged reaction, as the main product. These secondary products are formed via the Lewis acid catalyzed reaction of the intermediate epithiocycloalkane and a second molecule of the thioketone. In the reaction of thiobenzophenone and 1,2-epoxycyclohexane, trans-8,8- diphenyl-7,9-dioxabicyclo[4.3.0]nonane is formed in small amounts as an additional side product (Scheme 12). In all cases, the newly formed heterocycle and the carbocycle are trans-fused. This result is consistent with a nucleophilic ring-opening of the complexed oxirane by the thioketone via inversion of the configuration and subsequent formation of the O(1)-C(2) bond of the 1,3-oxathiolane (Scheme 13). The surprising formation of the fused 1,4-oxathiepan derivative 23 (Scheme 9) is in accordance with an ionic reaction mechanism (cf. Scheme 15).
Structure and Thermolysis of a 1,4,2-Oxatellurazole, a Novel Tellurium Containing Heterocycle
Minoura, Mao,Kawashima, Takayuki,Okazaki, Renji
, p. 1691 - 1692 (2007/10/02)
A novel tellurium containing heterocycle, 1,4,2-oxatellurazole, was characterized by X-ray crystallographic analysis which showed a remarkably small C-Te-C bond angle (79.4 deg), and its thermolysis afforded the corresponding ketone and isonitrile derived from an intermediary isotellurocyanate in a manner of 1,3-dipolar cycloreversion.
