Table 1 Identification of optimal reagents for constructing l-allo-End

1^a

10% Pd(OAc)₂, 2 equiv. CuCl₂, 2 equiv. NaHCO₃, MeCN, RT, 1 h

5%

2^a

3 equiv. tBuOCl, DCM, RT, 2 h

<5%

3^a

2 equiv. NIS, 4 equiv. NaHCO₃, MeCN, 0 °C, 0.5 h

52% (dr 5:1)

4^a

3 equiv. I₂, 4 equiv. NaHCO₃, MeCN, RT, 1 h

56%

5^a

3 equiv. I₂, 4 equiv. NaHCO₃, MeCN, 0 °C, 1 h

65% (dr 5:1)

6^b

3 equiv. I₂, 4 equiv. NaHCO₃, THF, 0 °C, 1 h

71% (dr > 15:1)

7^c

3 equiv. I₂, 4 equiv. NaHCO₃, MeCN, 0 °C, 1 h

61% (dr > 15:1)