Table 1 Cyclization of dicarboxylic acids.

From: Tandem synthesis of alternating polyesters from renewable resources

Entry

Complex

Anhydride

[PPNCl]/[M]

Dicarbonate

Time (h)

Yield (%)*

1

1

SA

—

Boc2O

13

0

2

1

SA

—

Eoc2O

50

12

3

1

SA

—

Moc2O

10

100

4

1

SA

1

Moc2O

8

100

5

1

GA

1

Moc2O

3

100

6

1

AA

1

Moc2O

6

95†

7‡

1

PA

1

Moc2O

0.5

97§

8

1

IA

1

Moc2O

7.5

100║

9

1

CA

1

Moc2O

1

100

10

2

PA

1

Moc2O

0.5

97§

11¶

2

PA

1

Boc2O

10

100

12

2

CA

1

Moc2O

1

100

13

3

CA

1

Moc2O

1

100

14

4

CA

1

Moc2O

1.5

100

  1. Abbreviations: AA, adipic anhydride; CA, camphoric anhydride; GA, glutaric anhydride; IA, itaconic anhydride; PA, pimelic anhydride; SA, succinic anhydride.
  2. All reactions performed in tetrahydrofuran with [anhydride]/[M]=100 at [anhydride]=1 M and [dicarbonate]=[anhydride] at 40 °C.
  3. *As determined by the integration of 1H NMR.
  4. †5% ester.
  5. ‡Reaction performed at room temperature.
  6. §3% ester.
  7. ║18% isomer (that is, citraconic anhydride).
  8. ¶Reaction performed at 50 °C.
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