Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• have been developed recently, including processes using alternative solvents such as ionic liquids and/or scCO2 [56][57][58][59][60][61]. The kinetic resolution of racemic 1-phenylethanol 54 was performed continuously in scCO2, using an immobilized lipase (Candida antarctica, Novozym 435) and vinyl

• )- 54 with immobilized lipase in a continuous scCO2- flow reactor. Enantioselective separation of Acetyl-D-Phe in a continuous flow reactor. Acknowledgements We thank the ETH Zürich, Astra Zeneca, and Merck, Sharpe & Dohme for generous financial support of the microreactor program in the Seeberger

N-acylation of ethanolamine using lipase: a chemoselective catalyst

• Mazaahir Kidwai,
• Roona Poddar and
• Poonam Mothsra

Beilstein J. Org. Chem. 2009, 5, No. 10, doi:10.3762/bjoc.5.10

• lipase (Novozym® 435) are described and optimum conditions for selective N-acylation rather than O-acylation are also discussed. Microwave assisted solution phase, solid supported and conventional methods were investigated and results were compared. There is a synergy between the enzyme catalysis and

• microwave irradiation. Keywords: chemoselective; lipase; microwave irradiation; zein number; Introduction Microwave assisted enzyme catalysis is a popular developing methodology in the field of green chemistry [1]. Enzymes have gained pivotal importance in the production of fine chemicals, pharmaceuticals

• lipase (CAL B Novozym® 435) with fatty acids or esters 1a–h and ethanolamine (2) under simultaneous microwave irradiation. Results and Discussion In the reaction of fatty acids 1a–d or esters of fatty acids 1e–h with ethanolamine (2), two types of acylated products are possible. Out of two possible

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• conditions resulted in a smooth conversion of the starting material into THF 89. Triol (+)-90 was obtained with lipase Amano AK desymmetrization. For the appropriate side chain attachment, the termini were differentiated to give lactone (−)-91. Reduction of (−)-91 followed by a Wittig reaction yielded fully

Diastereoselective and enantioselective reduction of tetralin- 1,4-dione

• E. Peter Kündig and
• Alvaro Enriquez-Garcia

Beilstein J. Org. Chem. 2008, 4, No. 37, doi:10.3762/bjoc.4.37

• precedent for procedures for the asymmetric synthesis of 9. The first involves as the key step kinetic resolution by enzymatic hydrolysis of the corresponding acetate with porcine pancreatic lipase giving (−)-9 in 47% yield and 95% ee [13]. A second approach uses a Pd-catalyzed asymmetric oxidation of meso

Large- scale ruthenium- and enzyme- catalyzed dynamic kinetic resolution of (rac)-1-phenylethanol

• Krisztián Bogár,
• Belén Martín-Matute and
• Jan-E. Bäckvall

Beilstein J. Org. Chem. 2007, 3, No. 50, doi:10.1186/1860-5397-3-50

• -phenylethanol (2) is addressed. The immobilized lipase Candida antarctica lipase B (CALB) was employed for the resolution, which shows high enantioselectivity in the transesterification. The ruthenium catalyst used, (η 5-C5Ph5)RuCl(CO)2 1, was shown to possess very high reactivity in the "in situ" redox

• racemization of 1-phenylethanol (2) in the presence of the immobilized enzyme, and could be used in 0.05 mol% with high efficiency. Commercially available isopropenyl acetate was employed as acylating agent in the lipase-catalyzed transesterifications, which makes the purification of the product very easy. In

• chemistry.[27] In the course of the chemo-enzymatic synthesis of optically pure alcohols and esters, Candida antarctica lipase B (CALB) was found to be one of the most active and selective biocatalysts compared to other enzymes. Lipases do not need the presence of a cofactor and they can be employed in pure