| Research Abstract |
This study was performed to synthesize new fully unsaturated five- (heteroles) and seven- (heteroepines) membered heterocyclic compounds containing group 15 and 16 heavier elements, and to elucidate their chemical properties such as structural feature, reactivity, thermal stability, and chirality.
1. Treatment of 1,4-dilithiobutadiene or 1,6-dilithiohexatriene systems, generated from the corresponding dibromo compounds and alkyllithium, with metal reagents (MX_2 or M : M=PPh, AsPh, SbPh, BiPh, S,Se, and Te) to result in ring closure giving the expected heteroles or heteroepines composed of group 15 and 16 heavier elements respectively. This procedure allowed to prepare theoretically possible three kinds of thieno [2,3-b], [3,4-b], and [3,2-b] heteroles, 3-benzoheteroepines, dibenzo-, and dithieno heteroepines most of which are a new class of heterocyclic ring system. All of the heteroepines prepared here are thermally labile toward heteroatom extrusion and gradually decomposed to naphth
… More
alene. The thermal stabilities of them were estimated from ^1H-NMR spectral analysis and the results revealed the following : (a) the 3-benzoheteroepines are far less stable than the corresponding 1-benzoheteroepines except for the phosphepine, (b) the thermal stabilities of the group 16 heteroepines decrease in the order Te>Se>S,but there is no pattern to the stabilities of the group 15 heteroepines.
We have also demonstrated that 0, b-dilithiostylene react with CoI_2 (Cp) (PPh_3) to give rise to cobaltaindene which can be easily converted to isoquinolines, quinolines, and dithiocoumarin by heating with nitrils, isocyanates and carbon disulfide in sealed tube respectively. These results indicates that the cobaltaindene is a useful synthon of various types of heterocyclic compounds.
2. The reaction of 1-benzoheteroles containing group 15 heavier elements with the modified Sharpless reagent or the Davis chiral oxaziridine reagent (0.5mol eq.) resulted in enantio-selective oxidation to afford optically active oxides and trivalent compounds. The isolated optically active stibindole and bismindole should be the first examples of stable unsymmetrical organoantimony (III) and bismuth (III) compounds. The optical purities of them were determined by the use of chiral Pd complex as a shift reagent of ^1H-NMR. Less
|
