1266612-72-9Relevant academic research and scientific papers
Stereoconvergent synthesis of chiral allylboronates from an E/Z mixture of allylic aryl ethers using a 6-NHC-Cu(I) catalyst
Park, Jin Kyoon,Lackey, Hershel H.,Ondrusek, Brian A.,McQuade, D. Tyler
, p. 2410 - 2413 (2011/04/25)
We present a 6-NHC-Cu(I) complex that provides α-substituted allylboronates using allylic aryl ether substrates. The method was discovered by comparison of the chemoselectivities exhibited by complexes 1a, 1b, 2, and 3. We observed that 1a preferentially reacts with electron-rich alkenes over electron-deficient alkenes. Development of an asymmetric method revealed that 1b reacts with both the E and Z isomers to provide the same absolute configuration without showing E-Z isomerization. This stereoconvergent reaction occurs with high yields (av 86%), high SN2′ selectivity (>99:1), and high ee (av 94%) and exhibits wide functional-group tolerance using pure E or Z isomer or E/Z alkene mixtures. The stereoconvergent feature enables the use of many different olefination strategies for substrate production, including cross-metathesis. Chiral allylboronates could be purified by silica gel chromatography and stored in the freezer without decomposition.
Six-membered N-Heterocyclic Carbene-based catalysts for asymmetric reactions
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Page/Page column 8; Sheet 9; Sheet 10, (2011/04/14)
The present invention provides a catalyst complex or ligand, and compositions thereof, for use in a variety of organic reactions having high reactivity and enantioselectivity. The catalyst is a N-heterocyclic carbene having three fused rings with first an
