Shell Oil Comapny

Hendricus J Heijmen

Roger A Sheldon

Aaldert J De Jong

Freddy Wattimena

Aaldert J deJong

An alpha-pivaloyl-substituted acetic acid ester of the formula (H.sub.3 C).sub.3 CCOCH.sub.2 COOR, wherein R is an optionally-substituted alkyl, aryl, alkaryl, or aralkyl group, is prepared by (a) reacting an alpha-pivaloyl-substituted malonic acid ester with a base selected from the class consisting of alkali metal alkoxides and compounds of the formula MXY, wherein M is an alkaline earth metal, X is an alkoxy group, and Y is either an alkoxy group or a halogen atom, and (b) acidifying the resulting reaction mixture.

Preparation of alpha-pivaloyl-substituted acetic acid esters

Aldehydes are prepared by hydrogenating a compound of general formula R'COOR, wherein R represents a hydrogen atom, an alkyl or an acyl group, or a metal, and R' represents an optionally substituted hydrocarbyl group having at most two alpha-hydrogen atoms, provided it has at most one beta-hydrogen atom, in case it has two alpha-hydrogen atoms, in the presence of a catalyst comprising at least one metal selected from rare earth metals and iron on an alumina-based carrier.

Process for the preparation of aldehydes

Novel cyclooctene derivatives of the formula: ##STR1## in which R.sup.1 and R.sup.2 each represents an alkyl group and R.sup.3 is hydrogen or an acyl group are disclosed along with their use as aroma chemicals and/or aroma chemical precursors and processes for their preparation.

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Amsterdam, Netherlands

Hendricus J Heijmen