CHEM 222 Study Guide - Final Guide: Stereoselectivity, Azeotrope, Column Chromatography
13 Apr 2012
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Lab 1 cycloadditon of dichlorocarbene to cyclohexene: carbenes = intermediates with two single bonds and a pair of non- bonding electrons on a carbon. Alpha elimination is the elimination of the alpha halide, to create the carbene. Quaternary ammounium salts are frequently used (organic in the organic layer, ammonium group in the aqueous). Example: benzyltriethylammonium chloride, trioctylmethylammonium chloride and tetrabutylammonium sulfate: the phase transfer catalyst is converted to its hydroxide salt in the presence of the base and this will equilibrate between the two layers. It was washed with ether to dissolve any 7,7-dichloronorcane remaining in the aqueous layer because it is much more soluble in ether than in water: after being dried with anhydrous sodium sulfate, it is roto-vapped. At the point where it is evaporated down to 5-8ml, bubbles are no longer observed in the r. b flask: then subjected to simple distillation.
