A simple and stereocontrolled syntheses of a 1β-methylcarbapenem key intermediate by means of organosilicon chemistry

Stereochemical Control in Organic Synthesis Using Silicon-Containing Compounds

“…Intramolecular delivery of the allylsilane group in the β-lactam 1750 was selective for attack on the iminium ion anti to the silyloxyethyl side chain, and in favor of the syn arrangement of the substituents at the two new stereogenic centers 1751 , setting up the β-methyl group for a 1β-methylcarbapenem synthesis (Scheme ) . A similar reaction was also successful between the same, homochiral β-lactam portion attached to a racemic 2-cyclohexenylsilane 1752 , where chiral recognition took place, only one diastereoisomer of the allylsilane 1752 reacted, and largely one diastereoisomer 1753 was formed in nearly 50% yield (Scheme ) …”

Recent advances in carbapenem chemistry (review)

“…Bismara and colleagues reported the stereoselective synthesis of a tricyclic carbapenem 8 [lle] by the application of the C(4)-alkylation developed by Ueo et al [31]. Hanessian's group found a novel preparation of the tricyclic derivatives by the combination of stereocontrolled decarboxylation and cyclization, utilizing the intramolecular Michael reaction [llf], and afterwards established a highly stereoselective and practical synthetic route to prepare 8 byutilizing diastereoselective protonation as a key step [lln].…”

Highly Diastereoselective Intramolecular Allylation Reactions of Mixed Silyl-Substituted Acetals

“…Indeed, examination of molecular models indicates that an antiperiplanar S E ‘ approach is not favorable. Reetz and co-workers have reported a novel intramolecular allyl transfer reaction to provide syn -1,3-diols 3a. In this example, a dimethylallylsilyl moiety is used to derivatize an aldol product with subsequent intramolecular delivery of the allyl group via a cyclic 10-membered ring induced by chelation to titanium.…”

“…There are few examples in the literature in which the silicon atom serves as a template to bring the allyl moiety and the electrophile together in an intramolecular reaction. To our knowledge, there are only two examples of an allylsilane addition reaction in which the silicon atom is “endocyclic” within a closed cyclic transition state for intramolecular delivery of the allyl group …”