Title:
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Cyclic sulfamidates as pseudo-alkyl halides in
Sp3 -based cross-coupling chemistry
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The use of cyclic sulfamidates as pseudo-alkyl halides in Sp3 -based cross-coupling chemistry
has been studied and two approaches were explored. The first approach involved a transition
metal-mediated cross-coupling of cyclic sulfamidates, including studies into the oxidative
addition step of the catalytic cycle. Various transition metal catalysts (palladium, nickel and
iron) and nucleophiles (zinc, boron, magnesium and tin reagents) were investigated. After
extensive screening, the desired cross-coupling was achieved under palladium-catalysed
Suzuki-Miyaura conditions, albeit in a low yield (20%) and with poor mass recovery.
The second approach, via enantiomerically pure f3- and y-aminoalkyl boronic esters, required
development of efficient conditions for borylation of cyclic sulfamidates. A range of known
and novel 1,2- and 1,3-cyclic sulfamidates was synthesised and subjected to the optimised
borylation conditions to determine the scope of this transformation. Mechanism of the
copper-catalysed borylation process was also explored, together with the utility of boronic
esters in sp3 _Sp2 and Sp3 _sp3 cross-coupling reactions.
Aminoalkyl boronic esters (from borylation of cyclic sulfamidates) were also assessed as
possible substrates for Matteson homologation. After extensive screening, it was found that
f3-aminoalkyl boronic esters (from 1,2-cyclic sulfamidates) can be homologated in a 50%
yield, while y-aminoalkyl boronic esters are completely unreactive to a range of
homologation conditions.
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