• Bulletin of the Korean Chemical Society
• /
• 제31권5호
• /
• pp.1280-1282
• /
• 2010

A new chiral catalyst was synthesized and found that it could catalyzed the asymmetric Michael reaction of ketones with nitroolefins smoothly at room temperature, giving the desired adducts in 71 - 92% yields with excellent diastereoselectivities and high enantioselectivities (up to 95% ee).

• Bulletin of the Korean Chemical Society
• /
• 제31권3호
• /
• pp.635-638
• /
• 2010

As a new strategy for the optimization of a chiral catalyst, the catalytic activity of the host-guest complexes of chiral bisphosphine bearing imidazolidinone was investigated in Rh-catalyzed asymmetric hydrogenation of enamide. Marginal enhancement in enantioselectivity was observed and the nature of interaction between host-guest was experimentally elucidated.

• KSBB Journal
• /
• 제15권5호
• /
• pp.415-422
• /
• 2000

Enzymatic resolution is becoming increasingly important in the production of optically active pharmaceutical drugs and is now challenging the traditional synthetic methods for production of a variety of chiral intermediates and products. This article reviews the recent advances in chirotechnology using enzymes as a catalyst to resolve chiral compounds. The review focuses on the recent trends in chirotechnology and the application of enzymes to the production of industrially valuable pharmaceutical drugs.

• Bulletin of the Korean Chemical Society
• /
• 제31권10호
• /
• pp.2973-2979
• /
• 2010

The newly synthesized homogeneous chiral Co(III) salen complexes were anchored non-covalently on the acidic sites of mesoporous Al-SBA-15. The Bronsted and Lewis acidic sites are attributed to the immobilization of fluorine functionalized chiral salen complexes on the supports. XRD, BET, TEM, FT-IR and ESCA (XPS) analyses were performed to characterize the property of support, and the structure of new homogeneous and heterogeneous chiral Co salen catalyst. The homogeneous and heterogeneous catalysts could be applied in asymmetric ring opening of epichlorohydrine (ECH) by water. They showed very high enantioselectivity and a good yield up to 99% in the catalytic synthesis of optically active products.

• 공업화학
• /
• 제26권2호
• /
• pp.132-137
• /
• 2015

BEA형 제올라이트를 알칼리용액으로 처리하여 결정구조 내에 메조세공이 형성되도록 제조하고, 세공 내에 균일계 키랄 Co(III) 살렌을 고정화시켰다. 메조세공 BEA-제올라이트에 고정화된 이핵형 Co-$GaCl_3$ 살렌 촉매는 말단 에폭사이드의 산소고리를 카르복실산으로 여는 키랄 반응에 대하여 높은 활성을 나타내었다. 이 반응을 통하여 라세믹 에폭사이드로부터 다양한 모노 에스테르 유도체를 중간 정도의 광학선택도(47~69 ee%)로 합성할 수 있었다. 키랄(S)-ECH를 반응물로 사용하면, 이들은 키랄 살렌 촉매 존재하에서 카르복시 산에 의하여 에폭사이드의 링이 광학선택적으로 열리며, 생성된 화합물을 염기용액에서 탈염산 처리하면 다시 에폭사이드 링이 형성되면서 광학순도가 매우 높은 모노에스터 에폭사이드 (R)-GB (98 ee% 이상)가 얻어졌다. 고정화촉매는 매우 용이하게 제조될 수 있었으며, 특별한 재생처리 없이 여러번 재사용하여도 촉매의 활성이 유지되었다.

• Bulletin of the Korean Chemical Society
• /
• 제26권2호
• /
• pp.225-226
• /
• 2005

• Bulletin of the Korean Chemical Society
• /
• 제25권3호
• /
• pp.347-348
• /
• 2004

• Bulletin of the Korean Chemical Society
• /
• 제25권10호
• /
• pp.1451-1452
• /
• 2004

• Bulletin of the Korean Chemical Society
• /
• 제35권1호
• /
• pp.98-102
• /
• 2014

The organocatalytic enantioselective Michael addition reaction promoted by chiral binaphthyl-modified squaramide catalyst have been developed, allowing facile synthesis of the corresponding chiral 2-amino-4H-chromenes derivatives with excellent enantioselectivity (up to 99% ee). The method reported represents a practical entry for the preparation of chiral 2-amino-4H-chromenes derivatives.

• Bulletin of the Korean Chemical Society
• /
• 제22권9호
• /
• pp.958-962
• /
• 2001

The chiral amine auxiliary mediated stereoselective alkylation reactions of glycinamides 1-6 and 15-17 using phase transfer catalyst (PTC) for liquid-solid extraction are described. The secondary N-(diphenylmethylene) glycinamides 1, 2 and 3 give better selectivities and yields than tertiary N-(diphenylmethylene) glycinamides 4, 5 and 6. Alkylation of the glycinamide 1 and 2 using 18-Crown-6 as a PTC in toluene at $-40^{\circ}C$ gives best selectivities and yields. Alkylations of N-(4-chlorophenylmethylene)glycinamides 15, 16 and 17 under same PTC conditions give $\alpha$, $\alpha-disubstituted$ amino acid derivatives 18, 19 and 20 with low diastereoselectivities.