Novel process for preparing semi-caronic aldehydes

A process for the preparation of a compound of the formula ##STR36## of cis structure, racemic or optically active wherein R is defined as above comprising reacting a compound of the formula ##STR37## wherein R has the above definition and the geometry of the double bond is Z with isopropylidene diphenyl sulfurane, to obtain a compound of the formula ##STR38## wherein R is defined as above and the configuration of the cyclopropane ring is cis and the dioxolane residue is hydrolyzed with a mineral or organic acid to obtain a compound of the formula ##STR39## wherein R and the configuration of the cyclopropane ring are defined as above and the 4,5 bond is cleaved under oxidizing conditions to obtain the compound of formula I.sub.B.

A process for the preparation of compounds of formula I.sub.B with a (1R,cis) configuration comprising reacting a compound of the formula ##STR40## of configuration (4S) where R has the above definition and the geometry of the double bond is Z with isopropylidene diphenyl sulfurane to obtain a compound of the formula ##STR41## of (4S) and (1R,cis) configuration at the cyclopropane level and the dioxolane residue is hydrolyzed with a mineral or organic acid to obtain a compound of the formula ##STR42## of (4S) configuration and (1R,cis) at the cyclopropane ring wherein R has the above definition and the 4,5 bond is cleaved under oxidizing conditions by the action of an oxidizing agent to obtain a compound of formula IB of (1R,cis) configuration.

A process for the preparation of a compound of formula I.sub.A with -1R trans configuration comprising reacting a compound of the formula ##STR43## of (4R) configuration wherein R has the above definition and the geometry of the double bond is E with an isopropylidene diphenyl sulfurane to obtain a compound of the formula ##STR44## of (4R) configuration and (1R,trans) at the cyclopropane ring in which R is defined as above and the dioxolane residue is hydrolyzed with a mineral or organic acid to obtain a compound of the formula ##STR45## of (4R) configuration and (1R,trans) at the cyclopropane ring wherein R is defined as above and the 4,5 bond is cleaved under oxidizing conditions by the action of an oxidizing agent to obtain a compound of formula IA of (1R,trans) configuration.

A process for the preparation of a compound of the formula ##STR48## of cis structure, racemic or optically active wherein R is defined as above comprising reacting a compound of the formula ##STR49## wherein R has the above definition and the geometry of the double bond is Z with isopropylidene diphenyl sulfurane to obtain a compound of the formula ##STR50## wherein R is defined as above and the configuration of the cyclopropane ring is cis and the dioxolane residue is hydrolyzed and the 4,5 bond are simultaneously cleaved with periodic acid or a periodate in the presence of sulfuric acid to obtain the compound of the formula I.sub.B.

A process for the preparation of compounds of formula I.sub.B with a (1R,cis) configuration comprising reacting a compound of the formula ##STR51## of configuration (4S) wherein R has the above definition and the geometry of the double bond is Z with isopropylidene diphenyl sulfurane to obtain a compound of the formula ##STR52## of configuration (4S) where R has the above definitions and the geometry of the double bond is Z with isopropylidene diphenyl sulfurane to obtain a compound of the formula ##STR53## of (4S) and (1R,cis) configuration at the cyclopropane level and the dioxolane residue is hydrolyzed and the 4,5 bond is simultaneously cleaved with periodic acid or a periodate in the presence of sulfuric acid to obtain a compound of formula (1B) of (1R,cis) configuration.

A process for the preparation of a compound of formula I.sub.A with -1R trans configuration comprising reacting a compound of the formula ##STR54## of (4R) configuration wherein R has the above definition and the geometry of the double bond is E with an isopropylidene diphenyl sulfurane to obtain a compound of the formula ##STR55## of (4R) configuration and (1R,trans) at the cyclopropane ring in which R is defined as above and the dioxolane residue is hydrolyzed and simultaneously the 4,5 bond is cleaved with periodic acid or a periodate in the presence of sulfuric acid to obtain a compound of formula 1 A of (1R,trans) configuration.

A process for the preparation of compounds of the formula ##STR59## with cis or trans structure in racemic or optically active form wherein R is selected from the group consisting of hydrogen, alkyl of 1 to 4 carbon atoms and aryl of 6 12 carbon atoms comprising reacting an optically active isomer, or racemate of the formula ##STR60## wherein R has the above definition and the wavy line indicates Z geometry with a gem-dimethyl cyclopropanation agent of the formula ##STR61## wherein X is selected from the group consisting of --P(Ar).sub.3, S(Ar).sub.2, Se(Ar).sub.2, --As(Ar).sub.2 and ##STR62## aryl and R.sub.1 is hydrogen or alkyl or 1 to 4 carbon atoms to obtain a compound of the formula ##STR63## wherein R has the above definition and the cyclopropane ring has the cis or trans configuration and simultaneously cleaving the 4,5 bond and hydrolyzing the dioxolane group with periodic acid or a periodate int he presence of sulfuric acid to obtain the corresponding compound of the formula I.

A process for the preparation of compounds of the formula ##STR66## with trans structure in racemic or optically active form wherein R is selected from the group consisting of hydrogen, alkyl of 1 to 4 carbon atoms and aryl of 6 to 12 carbon atoms comprising reacting an optically active isomer, or racemate of the formula ##STR67## wherein R has the above definition and the wavy line indicates E geometry with a gem-dimethyl cyclopropanation agent of the formula ##STR68## to obtain a compound of the formula ##STR69## wherein R has the above definition and the cyclopropane ring has the trans configuration and hydrolyzing the compound of formula IIIa with a mineral or organic acid to obtain a compound of the formula ##STR70## and then cleaving the 4,5 bond under oxidizing conditions to obtain the corresponding compound of formula I.sub.A.

A process for the preparation of compounds of the formula ##STR74## with trans structure in racemic or optically active form wherein R is selected from the group consisting of hydrogen, alkyl 1 to 4 carbon atoms and aryl of 6 to 12 carbon atoms comprising reacting an optically active isomer, or racemate of the formula ##STR75## wherein R has the above definition and the wavy line indicates E geometry with a gem-dimethyl cyclopropane agent of the formula ##STR76## obtain a compound of the formula ##STR77## wherein R has the above definition and the cyclopropane ring has the trans configuration and simultaneously cleaving the 4,5 bond and hydrolyzing the dioxolane group with periodic acid or a periodate in the presence of sulfuric acid to obtain the corresponding compound of formula I.sub.A.