| Attempts were made to control the outcome of carbene reactions by including the corresponding 3H-diazirine precursors within the cavities of cyclodextrins (CyD's) and faujasite (FAU) zeolites.;Photolyses of 3-azibicyclo[3.2.1]octane (63) were performed within CyD's and NaX FAU zeolite to alter the selectivity of the carbene intermediate, bicyclo[3.2.1]octan-3-ylidene (64). It was hypothesized that constriction of symmetric carbene 64 within each host would suppress the formation of bicyclo[3.2.1]oct-2-ene (65) and enhance that of tricyclo[3.2.1.03,8]octane (66). But only 65 was observed.;Photolyses of 1-azi-4-tert-butylcyclohexene ( 67) were performed within beta- and gamma-CyD's to alter the selectivity of the carbene intermediate, 4-tert-butylcyclohexanylidene (68). It was hypothesized that constriction of symmetric carbene 68 within the CyD hosts would suppress the formation of 4- tert-butylcyclohexene (69) and enhance that of 2,2-dimethylbicyclo[2.2.2]octane (70). But only 69 was observed.;Photolyses of 1-azi-2-methylcyclohexane (71) were performed within alpha-, beta- and gamma-CyD's to alter the selectivity of the carbene intermediate, 2-methylcyclohexanylidene (72). It was hypothesized that constriction of asymmetric carbene 72 within the CyD hosts would suppress the formation of 1-methylcyclohexene ( 73) and concomitantly enhance that of 3-methylcyclohexene (74 ) and bicyclo[4.1.0]heptane (75). However, no 75 was observed.;Photolyses of 3-azitricyclo[2.2.1.02,6]heptane ( 76) were performed within CyD's and NaY FAU zeolite to alter the selectivity of the carbene intermediate, tricyclo[2.2.1.02,6]heptan-3-ylidene (77). It was hypothesized that constriction of carbene 77 within each host would suppress the formation of 4 ethynylcyclopentene (78) and concomitantly enhance that of tetracyclo[2.2.1.0 2,6.03,5]heptane (79). But only 78 was observed. Since CyD innermolecular products were also formed, control experiments in relevant solvents were performed.;Photolyses of 3-chloro-3-phenyl-3H-diazirine ( 84) were performed within CyD's and FAU zeolites to foster the ring expansion of the carbene intermediate, chloro(phenyl)carbene (85). However, benzaldehyde (PhCHO) was formed instead of products deriving from 1-chloro-1,2,4,6-cycloheptatetraene (86). Since CyD innermolecular products were also formed, control experiments in relevant solvents were performed. |
