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。
Chiral Bicycle Imidazole Nucleophilic Catalysts: Rational Design, Facile Synthesis, and Successful Application in Asymmetric Steglich Rearrangement
作者:Zhenfeng Zhang、Fang Xie、Jia Jia、Wanbin Zhang
DOI:10.1021/ja109069k
日期:2010.11.17
A new type of chiral bicycle imidazole nucleophilic catalyst was rationally designed, facilely synthesized, and successfully applied in an asymmetric Steglich rearrangement with good to excellent yield and enantioselectivity at ambient temperature. Moreover, it can be easily recycled with almost no reduction of catalytic efficiency. This is the first example for the successful chiral imidazole nucleophilic
Amidine catalysed O- to C-carboxyl transfer of heterocyclic carbonate derivatives
作者:Caroline Joannesse、Carmen Simal、Carmen Concellón、Jennifer E. Thomson、Craig D. Campbell、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1039/b805850d
日期:——
The structural requirements of amidines necessary to act as efficient O- to C-carboxyl transfer agents are delineated and the scope of this process outlined through its application to a range of oxazolyl, benzofuranyl and indolyl carbonates.
A Dual-Catalysis Approach to the Asymmetric Steglich Rearrangement and Catalytic Enantioselective Addition of <i>O</i>-Acylated Azlactones to Isoquinolines
作者:Chandra Kanta De、Nisha Mittal、Daniel Seidel
DOI:10.1021/ja208156z
日期:2011.10.26
A dual-catalysis approach, namely the combination of an achiral nucleophilic catalyst and a chiral anion-binding catalyst, was applied to the Steglich rearrangement to provide α,α-disubstituted amino acid derivatives in a highly enantioselective fashion. Replacement of the nucleophilic co-catalyst for isoquinoline resulted in a divergent reaction pathway and an unprecedented transformation of O-acylated
Organic base effects in NHC promoted O- to C-carboxyl transfer; chemoselectivity profiles, mechanistic studies and domino catalysis
作者:Craig D. Campbell、Christopher J. Collett、Jennifer E. Thomson、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1039/c1ob05160a
日期:——
The O- to C-carboxyltransfer of oxazolylcarbonates promoted by triazolinylidenes, generated in situ with NEt3, shows a markedly different rate and chemoselectivity profile to the same reaction promoted by triazolinylidenes generated using KHMDS. The mechanism of these pathways has been probed through extensive crossover studies to understand this process. The use of NEt3 as a base allows domino multi-step
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.