4-芳基-2,3-二氢-4 H-嘧啶并[2,3- b ]苯并噻唑的合成及不对称酰基或羧基转移反应的催化性能
摘要:
合成了4-Aryl-2,3-dihydro-4 H -pyrimido [2,3- b ]苯并噻唑(4-Ar-DHPBs),它们在仲醇动力学和Steglich动力学拆分中具有催化活性和选择性重排和相关反应进行了评估。4-芳基-DHPB在1-苯基乙醇的酰基动力学拆分中显示出低的对映选择性。相反,他们以适中至优异的对映选择性催化了Steglich重排,证明了通过在DHPB的4位上引入取代基进行远程立体控制的可能性。
Isothiourea-Catalyzed Enantioselective Carboxy Group Transfer
作者:Caroline Joannesse、Craig P. Johnston、Carmen Concellón、Carmen Simal、Douglas Philp、Andrew D. Smith
DOI:10.1002/anie.200904333
日期:2009.11.9
Transferable skills: Enantiomerically pure isothioureas promote the O‐ to C‐carboxyl grouptransfer of oxazolyl carbonates with excellent levels of enantiocontrol (see scheme). The origin of the enantioselectivity of this process was probed mechanistically and rationalized computationally.
Isothiourea-Mediated Asymmetric O- to C-Carboxyl Transfer of Oxazolyl Carbonates: Structure-Selectivity Profiles and Mechanistic Studies
作者:Caroline Joannesse、Craig P. Johnston、Louis C. Morrill、Philip A. Woods、Madeleine Kieffer、Tobias A. Nigst、Herbert Mayr、Tomas Lebl、Douglas Philp、Ryan A. Bragg、Andrew D. Smith
DOI:10.1002/chem.201102847
日期:2012.2.20
The structural motif within a series of tetrahydropyrimidine‐based isothioureas necessary for generating high asymmetric induction in the asymmetric Steglich rearrangement of oxazolylcarbonates is fully explored, with crossover and dynamic 19F NMR experiments used to develop a mechanistic understanding of this transformation.
充分探索了一系列四氢嘧啶基异硫脲中的结构基序,这些结构对于恶唑碳酸酯的不对称Steglich重排产生高不对称诱导是必要的,并使用交叉和动态19 F NMR实验来发展对该转变的机理理解。
Catalytic enantioselective Steglich rearrangements using chiral N-heterocyclic carbenes
作者:Craig D. Campbell、Carmen Concellón、Andrew D. Smith
DOI:10.1016/j.tetasy.2011.04.001
日期:2011.4
The evaluation of a range of enantiomerically pure NHCs, prepared in situ from imidazolinium or triazolium salt precatalysts, to promote the catalytic enantioselective Steglich rearrangement of oxazolyl carbonates to their C-carboxyazlactones, is reported. Modest levels of enantioselectivity (up to 66% ee) are observed using oxazolidinone derived NHCs. (C) 2011 Elsevier Ltd. All rights reserved.