27784-76-5Relevant articles and documents
Griffiths et al.
, p. 275,280 (1976)
Lithium diisopropylamide-mediated reactions of imines, unsaturated esters, epoxides, and aryl carbamates: Influence of hexamethylphosphoramide and ethereal cosolvents on reaction mechanisms
Ma, Yun,Collum, David B.
, p. 14818 - 14825 (2007)
Several reactions mediated by lithium diisopropylamide (LDA) with added hexamethylphosphoramide (HMPA) are described. The N-isopropylimine of cyclohexanone lithiates via an ensemble of monomer-based pathways. Conjugate addition of LDA/HMPA to an unsaturated ester proceeds via diand tetra-HMPA-solvated dimers. Deprotonation of norbornene epoxide by LDA/HMPA proceeds via an intermediate metalated epoxide as a mixed dimer with LDA. Ortholithiation of an aryl carbamate proceeds via a mono-HMPA-solvated monomer-based pathway. Dependencies on THF and other ethereal cosolvents suggest that secondary-shell solvation effects are important in some instances. The origins of the inordinate mechanistic complexity are discussed.
General [4 + 1] Cyclization Approach to Access 2,2-Disubstituted Tetrahydrofurans Enabled by Electrophilic Bifunctional Peroxides
Gao, Min,Zhao, Yukun,Zhong, Chen,Liu, Shengshu,Liu, Pengkang,Yin, Qi,Hu, Lin
supporting information, p. 5679 - 5684 (2019/08/01)
A general [4 + 1] cyclization reaction of carbonyl nucleophiles with 2-iodomethylallyl peroxides, which function as unique electrophilic oxygen synthons, for the synthesis of a broad range of 2,2-disubstituted tetrahydrofurans is achieved under operationally simple conditions. The unprecedented asymmetric version of such reaction is also realized via chiral auxiliary-assisted cyclization, thus providing a distinct approach to access chiral tetrahydrofurans with high diastereoselectivities. The new method can be applied to the synthesis of core structure of posaconazole drug.
PROCESS FOR THE MANUFACTURE OF (E)-4-N,N-DIALKYLAMINO CROTONIC ACID IN HX SALT FORM AND USE THEREOF FOR SYNTHESIS OF EGFR TYROSINE KINASE INHIBITORS
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Page/Page column 17, (2015/07/16)
The present invention is directed to an efficient process for the manufacture of (E)-4-N,N- dialkylamino crotonic acid in HX salt form of formula I, wherein R1 and R2 independently denote C1-3-alkyl groups and Xˉ denotes an acid anion, such as the chloride, bromide, tosylate, mesylate or trifluoroacetate anion, with high quality, and a process for synthesis of EGFR tyrosine kinase inhibitors with heterocyclic quinazoline, quinoline or pyrimidopyrimidine core structure, using the acid addition salt I and activated derivatives thereof as intermediates.
