Studies on the catalytic cyanosilylation of carbonyl compounds and synthesis of pyrroles and bicyclic chiral aminoalcohols

Abstract

Three different topics are comprised in this thesis research: the first topic is the a dream combination for catalysis: highly reactive and recyclable scandium(Ⅲ) triflate-catalyzed cyanosilylations of carbonyl compounds in an ionic liquid, the second topic is tandem one-pot synthesis of substituted pyrroles by using the blaise reaction intermediate, and the last topic is synthesis of chiral bicyclic aminoalcohols. Part Ⅰ: The catalytic activity of lanthanide triflates, particularly scandium triflate, was increased dramatically when the solvent was changed from organic to an ionic liquid, [bmim][SbF_(6)], allowing the cyanosilylation of a variety of aldehydes and ketones with a turnover frequency up to 48 000 mol h^(-1) and a total turnover number of 100 000. Part Ⅱ: The tandem reaction of the Blaise reaction intermediates with propagylic compounds having leaving group (-OTs, -OMs, -Br) has been investigated for the regioselective synthesis of polysubstituted pyrroles via SN2 propargylation and 5-exo-dig cyclization. Part Ⅲ : Optically pure cis-fused 2-azabicyclo[3.3.0]octan-8-ols have been synthesized starting from commercially available racemic-cyclopenten-2-yl-acetic acid using (R)-α-methylbenzylamine as a sacrificial auxiliary. The absolute stereochemistry has been determined unambiguously by X-ray analysis.;졸업 논문의 연구는 크게 3 가지의 다른 주제로 구성되어 있다: Part Ⅰ의 주제는 촉매반응을 위한 dream combination : 이온성 액체를 사용하여 높은 반응성을 가지고 재사용 가능한carbonyl compounds의 scandium(Ⅲ) triflate-catalyzed cyanosilylations에 관한 연구이고, Part Ⅱ는 Blaise reaction intermediate를 사용한 substituted pyrroles의 tandem one-pot 합성에 관한 내용이다. 마지막 Part Ⅲ의 주제는 키랄 bicyclic aminoalcohols를 합성한 것에 관한 내용이다. Part Ⅰ: [bmim][SbF_(6)]를 사용한 lanthanide triflates, 특히 scandium triflate의 촉매 효능은 48 000 mol h^(-1) 이상의 turnover frequency 와 100,000의 total turnover number를 가지면서 다양한 aldehydes와 ketones 의 cyanosilylation을 현격히 증가시킨다. Part Ⅱ : Blaise reaction intermediates와 leaving group (-OTs, -OMs, -Br)을 가진 propargylic compounds의 tandem reaction은 SN2 propargylation과 5-exo-dig cyclization을 통하여 polysubstituted pyrroles을 위치선택적으로 합성할 수 있었다. Part Ⅲ : 출발물질은 라세믹 혼합물인 cyclopenten-2yl-acetic acid로, (R)-α-methylbenzylamine을 sacrificial auxiliary로 사용하여 광학적으로 순수한 cis-fused 2-azabicyclo[3.3.0]octan-8-ols을 합성하였고, 생성물의 입체화학은 X-ray 분석을 통해 확인하였다. 합성된 키랄 bicyclic aminoalcohols는 다양한 비대칭 촉매반응의 키랄 리간드 또는 유기분자촉매 등에 효과적으로 작용할 것으로 기대된다.