Table 1 Summary of reaction optimization studies.

From: Intermolecular 2+2 imine-olefin photocycloadditions enabled by Cu(I)-alkene MLCT

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Entry

Deviation from standard

Yield of 1Aa

1

None

55%

2

No TpCu

n.d.

3

No light

n.d.

4

3 equiv 1

79%

5

Entry 4 + 300 nm cut-on filter

39%

6

CuCl in place of TpCu

n.d.

7

CuOTf in place of TpCu

n.d.

  1. n.d. not detected.
  2. a1A was detected as a >95:5 exo:endo mixture and 62:48 diastereomer mixture at C2; yields determined by 1H NMR analysis of crude reaction mixtures using durene as an internal standard. Tp = hydrotris(pyrazolyl)borate, OTf = trifluoromethanesulfonate.
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