The ability of potassium fluoride to serve as a basic catalyst in the Knoevenagel reaction was determined using benzaldehyde and cyclohexanone with malononitrile, ethyl cyanoacetate, and ethyl malonate. Rubidium and cesium fluorides were shown to be somewhat better than potassium fluoride in the same reactions.

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The isolation of 2,3-diphenylthiiren 1,l-dioxide (2a) from the more acidic aa'-dibromodibenzyl sulphone has been accomplished with triethylamine in methylene chloride. We thank Dr. M. Rosen of CIBA, Summit, New Jersey for an authentic sample of (2a).

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The reaction of methyldichlorosilane with cis-1,3-, irons-1,3-, and 1,4-pentadienes in the presence of chloroplatinic acid has been investigated. All products were converted into the trimethylsilyl derivatives for glpc analysis and identification purposes. In the reaction involving 1,4-pentadiene, three products were found in a 75.5% yield with the following composition after methylation: l-trimethylsilyl-4-pentene (87.2%); cis-l-trimethylsilyl-2-pentene (9.3%); and cis-l-trimethylsilyl-3-pentene (3.5%). The reaction with trans-l,3-pentadiene gave three products in a 74.6% yield with the following composition after methylation: as-l-trimethylsilyl-2-pentene (42.0%); irans-2-trimethylsilyl-3-pentene (39.1%); and írons-l-trimethylsilyl-2-pentene (18.9%).The reaction of a's-1,3-pentadiene gave five products in a 82.2% yield, with the following composition after methylation: l-trimethylsilyl-4-pentene (1.3%); as-l-trimethylsilyl-2-pentene (23.2%); as-l-trimethylsilyl-3pentene (60.8%); irons-2-trimethyIsilyl-3-pentene (10.5%); and irons-l-trimethylsilyl-2-pentene (4.2%). A mechanism accounting for the products is proposed. This involves a platinum-diene-silane complex which then gives the various products. Besides 1,2 addition, in which silicon is found in the 1 position, reverse 1,2 addition, in which silicon is bonded to the 2 position, and 1,4 addition with silicon in the 1 position occur.This reverse 1,2 addition is accounted for by the stabilizing effect of the second double bond, and the predominance of cis products resulting from 1,4 addition is thought to be due to the original diene reacting in the cisoid conformation.