Selective syntheses and reactions of epoxy-, hydroxy-, and keto-substituted cyclohexyltriphenyltin compounds

Abstract

The epoxidation of cyclohex-3-enyltriphenyltin gave a 40/60 mixture of cis- and trans-3,4-epoxycyclohexyltriphenyltin. The reaction of the cis- and trans-epoxides, separately with lithium aluminum hydride, gave cis-3-hydroxycyclohexyltriphenyltin (>99%) and trans-3-hydroxycyclohexyltriphenyltin (100%) respectively. Hydroboration (BH 3) followed by basic oxidation of cyclohex-3-enyltriphenyltin gave cis-3-hydroxy- (∼42%), trans-3-hydroxy- (∼42%) as well as trans-4-hydroxy- (∼12%) and cis-4-hydroxy-cyclohexyltriphenyltin (∼4%). The attempted epoxidation of cyclohex-2-enyltriphenyltin gave only destannylation products due to the reactivity of allylic organotin compounds under electrophilic reaction conditions. Alternative hydroboration-oxidation of the allylic organotin compound also gave destannylation as well as 3- and 4-hydroxycyclohexyltriphenyltin compounds from rearrangement of the allylic to the homoallylic cyclohexenyltriphenyltin compound. Epoxidation of cyclohex-1-enyltriphenyltin gave 1,2-epoxycyclohexyltriphenyltin, which upon reaction with lithium aluminum hydride, gave destannylated compounds arising from hydride attack at C(2) and elimination of cyclohexanone and triphenyltin anion. cis-2-Methoxycyclohexyltriphenyltin was prepared stereospecifically by reaction of trans-1-bromo-2-methoxycyclohexane with triphenylstannylsodium, while the trans-2-hydroxycyclohexyltriphenyltin was also prepared in a stereospecific manner by reaction of cis-cyclohexene epoxide with triphenylstannylsodium. A discussion of these reactions as well as the reactivity of all the substituted cyclohexyltriphenyltin compounds with electrophilic reagents and their gas phase protonolysis reactions via chemical ionization mass spectroscopy will be presented.