3- Hexanone, 1-chloro

Dl-n-butyl-cadmium Chloroaoetyl chloride 1-Chloro-2-hexanone... 

The success of the last reaction depends upon the inertness of the ester carbonyl groups towards the organocadmium compound with its aid and the use of various ester acid chlorides, a carbon chain can be built up to any reasonable length whilst retaining a reactive functional group (the ester group) at one end of the chain. Experimental details are given for l-chloro-2-hexanone and propiophenone. The complete reaction (formation of ketones or keto-esters) can be carried out in one flask without isolation of intermediates, so that the preparation is really equivalent to one step. 

In contrast to the behavior of 3-hexyne in trifluoroacetic acid, addition of HCl in acetic acid yields essentially rra s-3-chloro-3-hexene (48%) and 3-hexanone (52%) as products, with less than 1% of the cis chloride (31,42,43). The 3-hexanone has been shown to arise from an intermediate vinyl acetate. The kinetics are complicated, but they seem to be of first order in substrate and second order in HCl. Added tetramethylammonium chloride increases the rate of product formation and changes the product composition to >95% trans-3-chloro-3-hexene and <5% 3-hexanone. A termolecular electrophilic addition via an intermediate such as 14 has been proposed (31,42) to account for these data. 

Draw the structures of the following compounds (a) 3-ethyl-4-methyl-2-hexanone (b) 2-chloro-buytl acetate (c) ethylbenzene id) 3-ethylcyclohexene (e) 2-methyl-3-pentanol (/) 2-methylpropyl methyl ether. 

The stereoselectivity of the reaction was studied with methyl-substituted 2-chlorocyclo-hexanones. The reaction of 2-chloro-4-methylcyclohexanone (7) with diethyl sodiomalonate gave 6-[bis(ethoxycarbonyl)methyl]-3-methylbicyclo[3.1.0]hexan-6-ol (8) in 59% yield. Similarly, reaction of 2-chloro-5-methylcyclohexanone (9) with diethyl sodiomalonate afforded a 49% yield of a 44 56 mixture of lOA and lOB, which were separable by preparative HPLC. 

On attempted vacuum-distillation of the 1-methylcyclopentyl hypochlorite obtained by chlorination of 1-methylcyclopentanol in alkaline solution, Cairns and Englund116 observed quantitative rearrangement of this material to 6-chloro-2-hexanone ... 

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