Reaction of chromyl chloride with some olefins. II. The oxidation of tetraarylethylenes

Abstract

Chromyl chloride oxidation of tetraphenylethylene results in a novel cyclization reaction giving 9,lOdiphenylphenanthrene in high yield. Some cyclization between geminal phenyl groups and cleavage of the olefinic bond occurs as evidenced by the presence of fluorenone and benzophenone as minor products. Polynuclear hydrocarbons such as 1,l'-binaphthyl and o-terphenyl which can be cyclized by Lewis acids are unreactive towards chromyl chloride. The observation of rotation about the central bond of a substituted tetraphenylethylene and of retardation of cyclization by substituent chlorine suggest that the oxidative cyclization proceeds by initial electrophilic attack at the olefinic bond to give a carbonium ion.

Ultrasound in oxochromium(VI)-mediated transformations. 2. Ultrasound-mediated preparation and applications of chromyl chloride

“…Freeman and Sharpless have investigated the synthetic and mechanistic aspects of the Étard-type sequence as applied to olefins. 19 Depending on solvent and temperature the typical products of the reaction of 1 with cyclic and acyclic olefins are epoxides, chlorohydrins, and vicinal dichlorides.19 Sharpless and Teranishi have described a preparation of -chloro ketones from the treatment of olefins with chromyl chloride in acetone followed by zinc dust reduction or sodium bisulfite treatment prior to workup (eq 3).5 We included ultrasound in the Sharpless-…”

Synthesis and Redox Behavior of Novel 9,10‐Diphenylphenanthrenes

“…The synthesis of the differently substituted 9,10-diphenylphenanthrenes 2b -2e is depicted in Scheme 2. According to a procedure of Gatzke et al [12], tetrakis(bromophenyl)ethene 1b [10] was treated with chromyl chloride (CrO 2 Cl 2 ) at 08 in CCl 4 for 24 h to give the corresponding phenanthrene 2b in 20% yield 4 ). It should be noted that, under these conditions, tetraphenylethene 1a reacted to 2a (10%), together with the C¼C cleavage product benzophenone.…”