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. Author manuscript; available in PMC: 2008 Dec 5.
Published in final edited form as: J Org Chem. 2007 Feb 2;72(3):756–759. doi: 10.1021/jo061339s

Table 1.

Results from reactions of β-lactam 5a with 7 to furnish 8 under varied reaction conditions (Scheme 2).

Entry Lactam Equiv Base Equiv Reaction Temp (°C) Yield (%) 8a Isomeric ratiob
1 4 1.5 LiHMDS − 40 81 41 : 1
2 4 1.5 LiHMDS − 40 to 0 82 36 : 1
3 4 1.5 LiHMDS 0 84 34 : 1
4 2 1.5 LiHMDS − 40 to 0 46 32 : 1
5 4 1.5 NaHMDS − 40 to 0 62 7 : 1
a

Yields for two steps;

b

The isomeric ratio (2′R,3′S): (2′S,3′R) was determined by HPLC.