Sh. Hang et Hs. Lee, AN ASYMMETRIC-SYNTHESIS OF A KEY INTERMEDIATE TO 1-BETA-METHYLCARBAPENEM ANTIBIOTICS, Tetrahedron letters, 36(37), 1995, pp. 6713-6716
1 beta-Methylcarbapenem 3 has been enantioselectively synthesized star
ting from ethoxyethyl ether 8 and methyl (R)-3-iodo-2-methylpropionate
via the intramolecular 1,3-dipolar cycloaddition of nitrone 6, in whi
ch the requisite chiral centers were settled.