Enantioselective Synthesis of Antiepileptic Drug: (-)-Levetiracetam—Synthetic Applications of the Versatile New Chiral N-Sulfinimine

Table 1

1,2-Addition of EtMgBr to chiral α-hydroxy-N-sulfinimine 3.

Entry	Solvent	Temp.	Time	Yield^a (%)
1	Et2O	−78°C	5-6 h	80 (0)
2	THF	−78°C	15 h	28 (47)
3	Toluene	−78°C	15 h	32 (53)
4	CH2Cl2	−78°C	15 h	28 (65)

^aYields in parentheses are for recovered starting materials.