KBS35-3 - Formation of propanoate intermediate (1.5 g scale)

[KlementineJBS]

Link to HIRAC.

Previous attempt is #129

Reaction scheme

Outcome

898.9 mg (3.70 mmol, 46%)

[KlementineJBS]

22.08.23

1. Dissolved SM (1.5143 g, 8.09 mmol) in ethyl acetate (30 mL)
2. Added KOtBu (911.1 mg, 8.09 mmol). Took an aliquot at 1 minute.
3. Left stirring at rt, took an aliquot at 25 min.
4. Added extra KOtBu (186 mg) at ~30 mins (to make a total of 1.097 g, 9.78 mmol, 1.2 equiv.)
5. Took an aliquot at 45 min and stopped stirring.

TLC indicated formation of multiple spots, as in previous attempts.

Two new spots appear, with the higher spot being present in the 25 and 45 minute aliquots but not the 1 minute aliquot. Hence, the 1 m aliquot was dissolved in water (1 mL) and extracted with ethyl acetate (2 x 2 mL), then rotovapped and NMR'd.

6. Added water (~ 100 mL) and extracted with ethyl acetate (3 x 100 mL)
7. Washed with brine (125 mL) and dried over mag sulphate before rotovapping

Crude mass: 1.7154 g

[KlementineJBS]

H NMR

Compared crude NMR, mystery spot NMR and NMR of purified product from #113. Interestingly, we can see a small amount of product present in the mystery spot NMR - indicating that the reaction is very rapid. Mystery spot resembles but doesn't exactly match NMR of "fractions C" from KBS35-1. Should check second product isolated from #129 and compared.

KBS35-3 cr_1.zip
KBS35-3 mystery spot_1.zip
KBS35-3 cr.pdf

[KlementineJBS]

Column conditions

W1 and F2-7 were rotovapped down.

Vial: 15.7319
Full vial: 16.6308
Mass: 898.9 mg (3.70 mmol, 46%)