A Highly Active Polymer-Supported Catalyst for Asymmetric Robinson Annulations in Continuous Flow
作者:Santiago Cañellas、Carles Ayats、Andrea H. Henseler、Miquel A. Pericàs
DOI:10.1021/acscatal.6b03286
日期:2017.2.3
preparation through Robinson annulation of enantiopure buildingblocks with both academic and industrial relevance, such as the Wieland–Miescher and Hajos–Parrish ketones, has suffered from important drawbacks, such as the need for high catalyst loading or extremely long reaction times. Here we report a heterogenized organocatalyst based on Luo’s diamine for fast and broad-scope enantioselective Robinson
Diastereoselective Synthesis of Complex <i>cis</i>-Hexahydroindanes by Reductive Alkylation
作者:Hilan Z. Kaplan、Victor L. Rendina、Jason S. Kingsbury
DOI:10.1021/jo400670y
日期:2013.5.3
An efficient and operationally simple approach to complex cis-hexahydroindanes is reported. Upon Birch reduction of unprotected, C4-alkylated tetrahydroindanols and electrophilic trapping of the tetrasubstituted enolate, cis-fused products are formed with a new stereogenic quaternary carbon. The reaction is convergent, completely diastereoselective, and shows a broad scope with regard to the electrophile
Evaluating β-amino acids as enantioselective organocatalysts of the Hajos–Parrish–Eder–Sauer–Wiechert reaction
作者:Stephen G. Davies、Angela J. Russell、Ruth L. Sheppard、Andrew D. Smith、James E. Thomson
DOI:10.1039/b711171a
日期:——
A systematic study of the effect of substitution within the β-amino acid framework indicates that both β2- and β3-amino acids catalyse the HajosâParrishâEderâSauerâWiechert reaction with poor to reasonable levels of enantioselectivity. These results led to the evaluation of the conformationally constrained β-amino acid (1R,2S)-cispentacin, which catalyses the HajosâParrishâEderâSauerâWiechert reaction with comparable or higher levels of enantioselectivity to L-proline.
A catalytic process for the synthesis of optically active C4-substituted tetrahydroindandiones using an asymmetric intramolecular aldol condensation reaction was developed. When 30 mol% of phenylalanine and 50 mol% of pyridinium p-toluenesulfonate were used under highly concentrated conditions, a variety of C4-substituted tetrahydroindandiones and octahydronaphthalenediones were obtained in high yield
An Enantioselective Approach to Pinguisane Sesquiterpenes: Total Synthesis of (-)-Pinguisenol and (-)-Isonaviculol
作者:Jhillu Singh Yadav、Shweta Singh、Saibal Das
DOI:10.1002/ejoc.201700395
日期:2017.5.18
Hajos-Parrish type ketone which successfully culminated as the firsttotalsynthesis of isonaviculol (10 steps, 6.6% overall yield) and natural pinguisenol (9 steps, 12% overall yield). The key reactions utilized are regioselective thioketal protection, stereoselective cyclopropanation using Furukawa's protocol , diastereoselective hydrogenation of olefin using Thalesnano H-Cube Pro flow reactor, Li-liq.NH3