Knochel's
group in Munich have recently disclosed how a variety of functionalised
heterocycles and sensitive acrylates can be rapidly magnesiated and
subsequently quenched with an electrophile under continuous
flow-through;conditions using a Uniqsis static mixer/reactor chip.
A key advantage is that, in contrast to typical batch procedures, these reactions required non-cryogenic conditions (typically 25C); moreover the procedure could be quickly scaled to 45 mmol without modification of the reaction conditions.
Metalations under flow-through conditions permited magnesiations that did not afford the desired product under batch conditions and acylates could be magnesiated and quenched to afford products with high stereoselectivities without concomitant polymerisation.
A
flow procedure for the metalation of functionalized heterocycles
(pyridines, pyrimidines, thiophenes, and thiazoles) and various
acrylates using the strong, non-nucleophilic base TMPMgCl⋅LiCl is
reported. The flow conditions allow the magnesiations to be performed
under more convenient conditions than the comparable batch reactions,
which often require cryogenic temperatures and long reaction times.
Moreover, the flow reactions are directly scalable without further
optimization. Metalation under flow conditions also allows magnesiations
that did not produce the desired products under batch conditions, such
as the magnesiation of sensitive acrylic derivatives. The magnesiated
species are subsequently quenched with various electrophiles, thereby
introducing a broad range of functionalities.A key advantage is that, in contrast to typical batch procedures, these reactions required non-cryogenic conditions (typically 25C); moreover the procedure could be quickly scaled to 45 mmol without modification of the reaction conditions.
Metalations under flow-through conditions permited magnesiations that did not afford the desired product under batch conditions and acylates could be magnesiated and quenched to afford products with high stereoselectivities without concomitant polymerisation.
Continuous Flow Magnesiation of Functionalized Heterocycles and Acrylates with TMPMgCl⋅LiCl†
see
http://onlinelibrary.wiley.com/doi/10.1002/anie.201404221/full
/////Continuous Flow Magnesiation, Functionalized Heterocycles, Acrylates , TMPMgCl⋅LiCl
MAKKAH, SAUDI ARABIA, MECCA
.
Mecca
City in Saudi Arabia
Mecca,
in a desert valley in western Saudi Arabia, is Islam’s holiest city, as
it’s the birthplace of the Prophet Muhammad and the faith itself. Only
Muslims are allowed in the city, with millions arriving for the annual
Hajj (pilgrimage). Dating from the 7th century, the central Masjid
al-Haram (Sacred Mosque) surrounds the Kaaba, the cloth-covered cubic
structure that’s Islam’s most sacred shrine.
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