Correction to “Synthetic, Functional Thymidine-Derived Polydeoxyribonucleotide Analogues from a Six-Membered Cyclic Phosphoester”

There are mistakes in the stereochemical structures for (R)-5 and (S)-5 in the original manuscript in the Abstract graphic, Scheme 1, Scheme 2, Figure 2, Figure 3, Table 2, and the Supporting Information (the chemical structures are shown here as original and corrected structures in Chart 1). These changes do not affect any of the conclusions. The corrected abstract graphic, figures, schemes, and tables are shown below. The corrected structures are provided in the revised Supporting Information. We apologize to the reader for any inconvenience.

Scheme 1. Synthetic Route from Thymidine to Monomer 5.

Scheme 2. Polymerization of 5 with 4-Methoxybenzyl Alcohol as the Initiator and TBD as the Catalyst.

Although the polymer is illustrated with only one regiochemistry and no stereochemistry, ³¹P NMR spectra suggested that the polymers contained regioisomeric and diastereoisomeric repeat units.

Figure 2.

Reaction coordinate diagram of using DMAP as activator to promote cyclization of 6 at the B3LYP/6-31+G* level of theory.

Figure 3.

Use of 1D-NOESY to identify the diastereomers (a) (S)-5 and (b) (R)-5, with atomic distances of 6.6 and 4.2 Å, respectively, calculated from DFT geometric optimization at the B3LYP/6-31+G* level of theory.

Table 2. Condition Screening for Cyclization of 6 with 7 Using Various Solvents and Bases at −78 °C.

entry	solvent	base	result	yield (%)	(R)/(S)a
1	THF	Et3N	oligomerization
2	THF	pyridine	oligomerization
3	THF	DMAP	oligomerization
4	THF	DIPEA	oligomerization
5	DMF	Et3N	oligomerization
6	DMF	pyridine	oligomerization
7	DMF	DMAP	oligomerization
8	DMF	DIPEA	oligomerization
9	CH2Cl2	Et3N	no reaction
10	CH2Cl2	pyridine	no reaction
11	CH2Cl2	DMAP	cyclization	58	88:12
12	CH2Cl2	DIPEA	cyclization	4	8:92

^aThe (R)/(S) ratio was determined by ³¹P NMR of reaction crude.

Chart 1. Original and Corrected Chemical Structures of (R)-5 and (S)-5.

Supporting Information Available

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/jacs.8b01661.

• Experimental procedures, spectroscopic data for all new compounds including ¹H, ¹³C, and ³¹P NMR spectra, TGA, DSC, and details of computational chemistry (PDF)