the formula i the reaction mixture should be maintained substantially water free during the process to obtain the highest yields the presence of water reduces the yield of the process by formation of by products and reaction with the reagents a small amount of dry alcohol of the formula r 5 oh wherein r 5 is the same as the r 5 of the organic orthoester or the orthosilicate can be introduced into the reaction mixture to speed initiation of the reaction but the addition of alcohol to the mixture is not required preferably the compounds prepared by the present process are compounds where r 1 r 2 r 3 and r 4 are hydrogen r 6 is alkyl of from 1 to about 6 carbon atoms or alkenyl of from 2 to about 6 carbon atoms and r 5 is alkyl of from about 1 to about 5 carbon atoms or alkenyl of from about 2 to about 5 carbon atoms the following examples are for illustration only and are not intended to be limiting in the examples all parts are by weight unless otherwise noted a mixture of 87 9 parts triethyl orthoformate 0 59 moles 109 3 parts 3 acetyl 5 butyl dihydro 2 3h furanone 0 59 mole 2 7 parts ethanol 0 059 mole and 0 87 parts.