Theoretical and Experimental Studies of Asymmetric Organozinc Additions to Benzaldehyde Catalyzed by Flexible and Constrained γ-Amino Alcohols
摘要:
The cis-decalin based gamma-amino alcohols, 1-5, were synthesized, resolved, and employed as catalysts in the addition of organozincs to benzaldehyde. Despite large facial differentiation in the RZn adducts of the ligands, the enantioselectivities were found to be moderate. Transition structure calculations were done using several quantum chemical methods to examine the underlying causes of the selectivity for three gamma-amino alcohols, 1, 2, and 3. The tricyclic mu-oxo (6/4/4), rather than the bicyclic six-membered (6/6), transition structures were found to explain the observed enantioselectivity for 2 and 3. MP2 calculations gave the best correlation to the experimental results compared to B3LYP and HIP calculations. The conformational flexibility of the chiral ligands was found to be an important factor in the selectivity.
Octahydro-7(1H)-quinolones. VII. A stereoselective synthesis of cis,trans-decahydro-3H,8H-benzo[i,j]quinolizine-3,8-dione.
作者:TAKEFUMI MOMOSE、SHUJI UCHIDA、TAKESHI IMANISHI
DOI:10.1248/cpb.27.215
日期:——
The conversion of 1-(3-chloropropyl)-cis-decahydroquinoline-2, 7-dione (3) into decahydro-3H, 8H-benzo [i, j] quinolizine-3, 8-diones (12a and 12b) was accomplished with retention of the parent stereochemistry. The stereochemistry of the tricyclic system was assigned from chemical and physical evidences. It was postulated that this successful ring closure in the cis ring system resulted from easy fulfilment of the stereoelectronic requirement, for intramolecular alkylation in 3, much reduced as compared to that for N-acrylyl-cis-octahydro-7 (1H)-quinolone (1b).
Theoretical and Experimental Studies of Asymmetric Organozinc Additions to Benzaldehyde Catalyzed by Flexible and Constrained γ-Amino Alcohols
作者:Manoranjan Panda、Puay-Wah Phuan、Marisa C. Kozlowski
DOI:10.1021/jo0262210
日期:2003.1.1
The cis-decalin based gamma-amino alcohols, 1-5, were synthesized, resolved, and employed as catalysts in the addition of organozincs to benzaldehyde. Despite large facial differentiation in the RZn adducts of the ligands, the enantioselectivities were found to be moderate. Transition structure calculations were done using several quantum chemical methods to examine the underlying causes of the selectivity for three gamma-amino alcohols, 1, 2, and 3. The tricyclic mu-oxo (6/4/4), rather than the bicyclic six-membered (6/6), transition structures were found to explain the observed enantioselectivity for 2 and 3. MP2 calculations gave the best correlation to the experimental results compared to B3LYP and HIP calculations. The conformational flexibility of the chiral ligands was found to be an important factor in the selectivity.
Momose,T. et al., Chemical and pharmaceutical bulletin, 1977, vol. 25, p. 1797 - 1802