2,3-Dihydro-4H-1,3-oxazin-4-ones, novel auxiliaries for the stereoselective synthesis of 1 beta-methylcarbapenems

Citation
Dk. Pyun et al., 2,3-Dihydro-4H-1,3-oxazin-4-ones, novel auxiliaries for the stereoselective synthesis of 1 beta-methylcarbapenems, SYNLETT, (12), 2001, pp. 1950-1952
Citations number
28
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
SYNLETT
ISSN journal
09365214 → ACNP
Issue
12
Year of publication
2001
Pages
1950 - 1952
Database
ISI
SICI code
0936-5214(200112):12<1950:2NAFTS>2.0.ZU;2-2
Abstract
Dihydrooxazinones 9 prepared from benzylcyanide in two steps serve as effic ient auxiliaries for the stereoselective synthesis of beta -methylcarbapene m intermediate 2. Reformatsky-type reactions of 4-acetoxyazetidinone with a -broinopropionyl dihydrooxazinone 10 provided beta -methylazetidinones 4 in high diastereoselectivities. The auxiliaries 9 were also easily removed in the Dieckmann cyclization leading to beta -methylcarbapenem skeletons. Pra ctical synthesis of beta -methylenolphosphates 2 from 4-acetoxyazetidinone 3 was achieved in three steps (61-77% overall yield).