Mukaiyama-Michael Reactions with<i>trans</i>-2,5-Diarylpyrrolidine Catalysts: Enantioselectivity Arises from Attractive Noncovalent Interactions, Not from Steric Hindrance
作者:Eeva K. Kemppainen、Gokarneswar Sahoo、Antti Piisola、Andrea Hamza、Bianka Kótai、Imre Pápai、Petri M. Pihko
DOI:10.1002/chem.201304240
日期:2014.5.12
the predicted and observed stereoselectivities. The analysis of intermolecular forces reveals that the enantioselectivity is mostly due to stabilizing noncovalentinteractions between the reacting partners, not due to sterichindrance. The role of attractivenoncovalentinteractions in enantioselective catalysis may be underappreciated.
Palladium on Charcoal as a Catalyst for Stoichiometric Chemo- and Stereoselective Hydrosilylations and Hydrogenations with Triethylsilane
作者:Sakari Tuokko、Petri M. Pihko
DOI:10.1021/op5003209
日期:2014.12.19
Stoichiometric quantities of triethylsilane in the presence of activated Pd/C as the catalyst can be used to effect chemo-, regio-, and stereoselective hydrosilylation and transfer hydrogenation reactions. α,β-Unsaturatedaldehydes and ketones are selectively hydrosilylated to give the corresponding enol silanes or transfer hydrogenated to give the saturated carbonyl compounds in the presence of other
Studies on the synthesis of the quartromicins: partial stereochemical assignment of quartromicins A3 and D3 and diastereoselective synthesis of the endo- and exo-spirotetronate subunits
作者:William R Roush、David A Barda、Chris Limberakis、Roxanne K Kunz
DOI:10.1016/s0040-4020(02)00656-7
日期:2002.8
A partial stereochemical assignment of quartromicins A3 and D3 is presented, along with diastereoselective syntheses of the endo- and exo-spirotetronates 1 and 2, corresponding to the galacto and agalacto fragments of the proposed quartromicin stereostructure. The key steps of these syntheses are highly enantio- and diastereoselective Lewis acid catalyzed Diels–Alder reactions of 1,1,3,4-tetrasubstituted
Rapid Access to the Tricyclic Spirotetronic Core of Abyssomicins
作者:Alexandros L. Zografos、Athanasios Yiotakis、Dimitris Georgiadis
DOI:10.1021/ol051872e
日期:2005.9.1
[reaction: see text] Abyssomicins, a novel class of polyketide antibiotics, are characterized by an unprecedented spirotetronic tricyclic subunit in their structure. In this letter, a short synthesis of a suitably functionalized tricyclic precursor of abyssomicins is reported. Key steps of the synthesis are (i) the highly stereoselective Al(III)-tethered Diels-Alder reaction and (ii) the tandem Dieckmann