Studies on lactams. 81. Enantiospecific synthesis and absolute configuration of substituted .beta.-lactams from D-glyceraldehyde acetonide

Linear and Cyclic Depsipeptidomimetics with β‐Lactam Cores: A Class of New αvβ3 Integrin Receptor Inhibitors

“…The starting β‐lactams 6 a and 6 b were prepared as essentially single diastereomers by standard cycloaddition between benzyloxyacetyl chloride and imines 5 a and 5 b ( Scheme ) in the presence of triethylamine followed by hydrogenolytic removal of the benzyloxy group . With α‐hydroxy‐β‐lactams 6 a and 6 b to hand, cyclodepsipeptides 15 a and 15 b were synthesized as shown in Schemes and , below.…”

Ring Expansion versus Cyclization in 4‐Oxoazetidine‐2‐ carbaldehydes Catalyzed by Molecular Iodine: Experimental and Theoretical Study in Concert

“…[11] Optically pure trans-4-oxoazetidine-2-carbaldehyde epim-1c was prepared adopting literature methodology. [12] Initial attempts to promote the cyanosilylation reaction of 4-oxoazetidine-2-carbaldehydes with tert-butyldimethylsilyl cyanide (TBSCN) were performed with 3-alkyl-A C H T U N G T R E N N U N G (aryl) substrates 1a and 1b by the use of molecular iodine as the catalyst. Unfortunately, the starting aldehyde was recovered as the main component together with small amounts of the O-silylated cyanohydrin 2a when a three-fold excess of TBSCN was used (Scheme 1).…”

Advances in the chemistry of ?-lactam and its medicinal applications

“…35,38–40 For example, the [2+2] cycloaddition of various ketenes with chiral imines 9 of D-glyceraldehyde acetonide ( 8 ), derived from D-mannitol via 7 , afforded cis -β-lactams 10 exclusively in 45–70% yield. 41,42 The acetonide moiety of β-lactams 10 was deprotected to the corresponding β-lactam diols, which were oxidized by ruthenium tetroxide, followed by diazomethane esterification, to afford the 4-carbomethoxy-β-lactams. 41 The β-lactam diols was also converted into the corresponding 4-formyl-β-lactam 11 , which are versatile synthetic intermediates for further manipulations.…”

“…41,42 The acetonide moiety of β-lactams 10 was deprotected to the corresponding β-lactam diols, which were oxidized by ruthenium tetroxide, followed by diazomethane esterification, to afford the 4-carbomethoxy-β-lactams. 41 The β-lactam diols was also converted into the corresponding 4-formyl-β-lactam 11 , which are versatile synthetic intermediates for further manipulations. 13,42–44 …”