20440-81-7Relevant articles and documents
Cross-Coupling Reaction of tert-Alkyl halides with Grignard Reagents in Dichloromethane as a Non-Lewis Basic Medium
Ohno, Masatomi,Shimizu, Kazuo,Ishizaki, Kenichi,Sasaki, Tadashi,Eguchi, Shoji
, p. 729 - 733 (2007/10/02)
In dichloromethane as a non-Lewis basic solvent, 1-haloadamantane 1 underwent a cross-coupling reaction with Grignard reagents to give bridgehead-substituted products 3-16 in moderate yields.In this case the same kind of halogen in both 1 and a Grignard reagent was favored; if not, functional exchange (i.e., 1a to 1c) occurred first.The reaction using 5-hexenylmagnesium bromide as a radical probe afforded uncyclized/cyclized coupling products in a 6/4 ratio.These fact suggested the significant participation of the single-electron-transfer process in these reactions.The present method could be extended to tert-butylation with some Grignard reagents.Interestingly, 1,3-dichloro-3-methylbutane coupled with butylmagnesium chloride selectively at the tertiary position. for the above displacement reaction of 1, an organozinc was also found to be effective.
Direct Geminal Dimethylation of Ketones and Exhaustive Methylation of Carboxylic Acid Chlorides Using Dichlorodimethyltitanium
Reetz, Manfred T.,Westermann, Juergen,Kyung, Suk-Hun
, p. 1050 - 1057 (2007/10/02)
The reaction of ketones with an excess of (CH3)2TiCl2 (6) leads to the replacement of the carbonyl oxygen atom by two methyl groups.This mild method of direct geminal dimethylation involves Grignard-type addition followed by formation of tertiary carbocations which are captured by methyltitanium species.Additional functional groups such as primary alkyl chlorides, thioethers, aromatics, ethers and esters are tolerated, but not thioketals.The procedure has been applied to the synthesis of (+/-)-cuparene (44).Similarly, carboxylic acid chlorides are converted to tert-butyl derivatives.
