The Action of Lithium Aluminum Hydride on a β-Lactam¹

Preparation of azetidines from 1,3-aminopropanols

“…The filtrate was acidified to pH 3, extracted with EtOAc (3 x 250 ml) and the extract dried and evaporated to give ~xR,3S)-a-isopropyl-3-t-butoxycarbonylamino-2-o~azetidin-1jtlacetic acid (1 1.7 g, 65%), m.p. (5).-The amide (4) ( 10 g, 22 mmol) in T H F (170 ml) was reduced with diborane, generated from boron trifluorideediethyl ether (7.1 g, 50 mmol) and sodium borohydride (1.1 g, 30 mmol), in the manner described above. After the usual treatment with aqueous ammonium chloride, the product was chromatographed through silica (350 g), using 1:2 EtOAc-light petroleum as eluant to give the title amino alcohol (15).-3-Benzoylaminopropanoic acid l 6 (9.65 g, 0.05 mol) in dry T H F (60 ml) was added dropwise, during 30 min, to an ice-cooled solution of lithium aluminium hydride (3.8 g, 0.1 mol) in dry THF (80 ml).…”