42238-20-0Relevant academic research and scientific papers
Enantioselective Conjunctive Cross-Coupling of Bis(alkenyl)borates: A General Synthesis of Chiral Allylboron Reagents
Edelstein, Emma K.,Namirembe, Sheila,Morken, James P.
supporting information, p. 5027 - 5030 (2017/05/04)
Palladium-catalyzed conjunctive cross-coupling is used for the synthesis of enantioenriched allylboron reagents. This reaction employs nonsymmetric bis(alkenyl)borates as substrates and appears to occur by a mechanism that involves selective activation of the less substituted alkene followed by migration of the more substituted alkene during the course of a Pd-induced metalate rearrangement.
3-Chloro-1-lithiopropene, a functional organolithium reagent, and its reactions with alkylboronates to give 3-alkylprop-1-en-3-ols
Smith, Keith,Elliott, Mark C.,Jones, D. Heulyn
, p. 9526 - 9531 (2013/10/08)
The reagent 3-chloro-1-lithiopropene (4) can be generated by treating 1-bromo-3-chloropropene with t-BuLi. It is unstable but if generated at low temperature in the presence of alkylboronic esters, such as 3, is trapped in situ to give rearrangement products 2, which on oxidation give 3-alkylprop-1-en-3-ols in good yields. The reaction works for primary, secondary, benzylic, and even tertiary alkylboronic esters, providing allylic alcohols bearing almost any alkyl group available using organoborane chemistry and incorporating all features of such groups.
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.
