Organocatalytic Enantioselective Synthesis of Indandione-derived Spiro Compounds Using by Cinchona Alkaloid-derived Organocatalysts

• Main Authors: Hsieh, Kai-Hong, 謝鎧鴻
• Other Authors: Lin, Wen-Wei
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/19078200983750298607

碩士 === 國立臺灣師範大學 === 化學系 === 104 === In my thiesis, the cinchona alkaloid derived organocatalysts were utilized for the synthesis of cyclohexanone and cyclopentanone derivatives via the covalent or non-covalent asymmetric organocatalysis. In the first part, a new class of coumarin derivatives, bearing an electrophilic and a nucleophilic site at the same time, have been developed. Cinchona alkaloid-derived chiral hydrogen bonding catalysts were utilized to carry out the [3+2] cyclization of these coumarin derivatives with 2-alkylidene indandiones. The corresponding spiro products bearing four stereocenters, including an all-carbon quaternary center, were obtained as single diastereomers with high enantioselectivity. The Michael addition intermediate was also isolated and a few control experiments have been performed to support the proposed mechanism. In second part, a cinchona-alkaloid derived chiral primary-amine-catalyzed enantioselective spirocyclohexanones derivatives is demonstrated. Both the enantiomeric forms of the trans isomer are obtained in excellent yields and enantioselectivities. Mechanistic investigations revealed two competing pathways, a concerted Diels−Alder reaction and a stepwise Michael addition, for the formation of corresponding products.