. 2021 Jul 19;6(30):19956–19963. doi: 10.1021/acsomega.1c02940

Table 1. Optimization of Reaction Conditions.

entry	H₂SO₄ (%)	time (h)	D content (%)^a	yield (%)^b
1	2.4	65	77^c	n.d.^d
2	9.7	110	91^c	n.d.^d
3	20	45	82^e	98
4^f	20	45	81^c	n.d.^d
5	20^g	18	97^e	99
6^h	20^g	18	93^e	93

Indicated as the average D incorporation at C2 and C4–C7.

Isolated yield.

D content was calculated based on the ¹H NMR spectra of the reaction mixture.

Not determined.

D content was calculated based on the ¹H NMR spectra of the isolated product.

With light shielding.

D₂SO₄ was used instead of H₂SO₄.

The reaction was performed in a 0.3 M solution.