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SUMMARY:Controlling selectivity in chemical catalysis using non-covalent i
 nteractions - Dr. Robert J. Phipps (University of Cambridge)
DTSTART:20221103T181000Z
DTEND:20221103T193000Z
UID:TALK192275@talks.cam.ac.uk
CONTACT:Agustin
DESCRIPTION:This lecture will describe our research program which seeks to
  develop new catalytic strategies based on attractive non-covalent interac
 tions to tackle selectivity challenges in modern synthetic methodology. No
 n-covalent interactions play a crucial role in all manner of chemical and 
 biological processes. In recent times\, the incorporation of non-covalent 
 interactions into the design of small molecule catalysts has revolutionise
 d the field of enantioselective catalysis. Our research is centered around
  applying catalyst designs incorporating non-covalent interactions to tack
 le foremost selectivity challenges in synthetic chemistry\, concerning bot
 h positional selectivity and enantioselectivity. \n\n\nThe lecture will de
 scribe initial projects focussed on the challenge of site-selectivity whic
 h commenced with the development of a bifunctional ligand based on ion-pai
 ring for controlling site-selectivity in iridium-catalysed borylation. We 
 have subsequently applied a bifunctional ligand strategy to control site-s
 electivity in Suzuki-Miyaura couplings of substrates bearing multiple inst
 ances of the same halide\, in this case using a sulfonated phosphine. Subs
 equent investigations will be described which probe the feasibility of usi
 ng the chiral cation associated with the ligand as the sole source of chir
 ality to achieve an enantioselective remote borylation of a symmetrical su
 bstrate and describe how we were able to realise the desymmetrising boryla
 tion on two distinct classes of substate\, to form both chiral-at-carbon a
 nd chiral-at-phosphorous compounds. This approach has been further applied
  to Rhodium catalysed C-H amination. We synthesised an anionic version of 
 Rh2(esp)2 and have shown that\, when paired with chiral cations\, this cat
 alyst gives excellent enantioselectivies for C-H amination of substrates b
 earing a pendant hydroxy group\, which we believe interacts with the catal
 yst sulfonate group through hydrogen bonding.\n\n!https://www.chemsoc.ch.c
 am.ac.uk/static/event_images/Phipps.png!\n\n
LOCATION:Dept of Chemistry\, Wolfson Lecture Theatre 
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