Expanding the Utility of Brønsted Base Catalysis: Biomimetic Enantioselective Decarboxylative Reactions
作者:Yuanhang Pan、Choon Wee Kee、Zhiyong Jiang、Ting Ma、Yujun Zhao、Yuanyong Yang、Hansong Xue、Choon-Hong Tan
DOI:10.1002/chem.201100687
日期:2011.7.18
of simple esters, the use of them as nucleophiles in directasymmetric transformations is a long‐standing challenge in synthetic organic chemistry. Nature approaches this difficulty through a decarboxylative mechanism, which is used for polyketide synthesis. Inspired by nature, we report guanidine‐catalyzed biomimetic decarboxylative CC and CN bond‐formation reactions. These highly enantioselective
Gaining Insight Into Reactivity Differences Between Malonic Acid Half Thioesters (MAHT) and Malonic Acid Half Oxyesters (MAHO)
作者:Sean P. Bew、G. Richard Stephenson、Jacques Rouden、Jeremy Godemert、Haseena Seylani、Luis A. Martinez-Lozano
DOI:10.1002/chem.201605148
日期:2017.4.3
An efficient two‐step synthesis of structurally and functionally diverse thiophenol‐ and (cyclo)alkyl‐derived malonicacid half thioesters (MAHTs) and phenol‐derived malonicacid half oxyesters (MAHOs) has been achieved using cheap, readily available and easily handled starting materials. The synthesis of the MAHTs and MAHOs (the majority of which have not been previously reported) is readily scalable
Chemoenzymatic Total Synthesis and Structural Diversification of Tylactone-Based Macrolide Antibiotics through Late-Stage Polyketide Assembly, Tailoring, and C—H Functionalization
作者:Andrew N. Lowell、Matthew D. DeMars、Samuel T. Slocum、Fengan Yu、Krithika Anand、Joseph A. Chemler、Nisha Korakavi、Jennifer K. Priessnitz、Sung Ryeol Park、Aaron A. Koch、Pamela J. Schultz、David H. Sherman
DOI:10.1021/jacs.7b02875
日期:2017.6.14
Polyketide synthases (PKSs) represent a powerful catalytic platform capable of effecting multiple carbon-carbon bond forming reactions and oxidation state adjustments. We explored the functionality of two terminal PKS modules that produce the 16-membered tylosin macrocycle, using them as biocatalysts in the chemoenzymatic synthesis of tylactone and its subsequent elaboration to complete the first total
Direct Access to β-Trifluoromethyl-β-hydroxy Thioesters by Biomimetic Organocatalytic Enantioselective Aldol Reaction
作者:Jin Hyun Park、Jae Hun Sim、Choong Eui Song
DOI:10.1021/acs.orglett.9b01469
日期:2019.6.21
decarboxylative catalytic aldol reaction of trifluoromethyl ketones with malonic acid half-thioesters (MAHTs) is described. Utilizing cinchona-based thioureas as highly efficient polyketide synthase-mimic catalysts, chiral tertiary aldols, β-trifluoromethyl-β-hydroxy thioesters, were obtained in up to 99% yield and 95% ee. Facile transformation of the thioester moiety of the aldoladducts showcases the synthetic
Amine-Catalyzed Cascade Synthesis of 3,4-Diunsubstituted Coumarins
作者:Jia Wei、Pengcheng Wang、Qianfa Jia、Jiaoyao Huang、Zhiyun Du、Kun Zhang、Jian Wang
DOI:10.1002/ejoc.201300538
日期:2013.7
We disclose an efficient route to synthesize 3,4-diunsubstitutedcoumarins through a cascade organocatalytic reaction. The reaction is catalyzed by using of a combination of benzylamine (10 mol-%) and triethylamine (10 mol-%). Various salicylaldehydes were tested, and the corresponding coumarin products were obtained in good to high yields under mild and metal-free reaction conditions.