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KlementineJBS / USYD_PhD_ELN

This repository forms the electronic laboratory notebook (ELN)for Klementine Burrell-Sander's PhD's
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KBS29-2 - Appel reaction on KBS28 #63

Closed KlementineJBS closed 10 months ago

KlementineJBS commented 1 year ago

Link to HIRAC and master page. Method taken from J. Batten's PhD thesis (2022).

KBS29 - Appel reaction (CBr4).docx

Previous attempt is #57

Reaction scheme

KBS29 - Appel reaction (CBr4)

Outcome

Unclear. Lots of SM left.

KlementineJBS commented 1 year ago

Used SM = 580 mg, 2.58 mmol

CBr4 - used 1.014 g, 3.10 mmol, 1.2 equiv. PPh3 - used 812.5 mg, 3.10 mmol, 1.2 equiv.

KlementineJBS commented 1 year ago

07.03.23

TLC indicated reaction was not yet complete. Added another 1 equiv. of both CBr4 and PPh3 at 4.30 pm. Left stirring.

KlementineJBS commented 1 year ago

08.03.23

Reaction went dry overnight, leaving a gummy red product. Added additional 5 mL DCM and left stirring. TLC still indicated reaction was incomplete.

NMR'd to check - peak at 4.84.

SM has peak at 4.98. Product has peak at 4.74.

Unsure what 4.84 is - could potentially be PPh3 ester intermediate.

KBS29-2 RM_1.zip KBS29-2 RM.pdf

Afternoon

Top spot appears to be an intermediate - possibly the PPh3 ester.

Decided to add KBr as a bromide source (153.5 mg, 1.29 mmol, 0.5 equiv.)

KlementineJBS commented 1 year ago

13.03.23

Final TLC (40% ethyl acetate in hexanes). Top spot (intermediate) no longer seems to be present - hopefully addition of bromide helped to push reaction forward. However, SM remains.

Appearance after final TLC

Rotovapped down - mixture was very thick and gummy, and foamed up when rotovapping. Unreacted potassium bromide was present in the bottom of the flask.

In future - may need to find a solvent that KBr dissolves better in.

KlementineJBS commented 1 year ago

KBS29-2 cr.pdf

13.03.23

Syringe filtered when transferring solution from RBF to vial - this made the solution far clearer/less cloudy and seems to have made it less prone to foaming up. Material is thick and gummy - like strawberry jam.

Need to use ether to remove traces of DCM - add 2-3 mL ether, rotovap down and repeat until crystalline product is obtained,

NMR

KBS29-2 cr_1.zip KBS29-2 cr.pdf

Strong evidence of Br formation (peak is at 4.74, no peak at 4.98). Other peaks are mostly solvent impurities (ether, DCM).

KlementineJBS commented 1 year ago

28.03.23

H NMR

Column Fractions Empty vial (g) Mass (mg) Identification
1 8-9 16.1079 46.1 Mixture - product + SM or mystery compound
1 10-16 15.9595 609.6 Triphenyl phosphine oxide
2 8-9 15.9472 47.4 Product, small amount of SM/mystery compound
2 10-16 15.9650 ~ 1 g uncertain
2 18-28 15.7640 452.2 nil

KBS29-2 C2 F18-28_1.zip KBS29-2 C1 F10-16_1.zip KBS29-2 C1 F8-9_1.zip KBS29-2 C2 F8-9_1.zip

Need to assess last NMR (C2 10-16) and run a carbon on product vs SM - possibly using cleaner material from previous attempts, if some remains.

KlementineJBS commented 1 year ago

Need to assess last NMR (C2 10-16) and run a carbon on product vs SM - possibly using cleaner material from previous attempts, if some remains.

Should also ask Nick if there is a way of doing mass spec that will differentiate between SM and product well enough.

KlementineJBS commented 1 year ago

C NMR

Sample Peaks Identification
KBS28-1 28.32, 56.10 OH compound
KBS29-2 C2 F8-9 21.30, 50.42 probably OH?
PPh3 oxide none under 77 PPh3 oxide
KBS29-2 C1 F10-16 20.61, 28.21, 35.98, 49.02 mixture of OH/Br ?

KBS29-2 column carbon NMRs.zip KBS29-2 column carbon NMRs.pdf