Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• Schotten–Baumann conditions [62][63]. Thus, K2CO3 (→ pH = 10) as the base prevented saponification of the side chain methyl ester functions (as observed with hydroxide salts). Nevertheless, in the acylation of the glutamic acid derivative 8e the corresponding pyroglutamic acid derivative 2g resulting from

Diastereoselective radical addition to γ-alkyl-α-methylene-γ-butyrolactams and the synthesis of a chiral pyroglutamic acid derivative

• Tomoko Yajima,
• Eriko Yoshida and
• Masako Hamano

Beilstein J. Org. Chem. 2013, 9, 1432–1436, doi:10.3762/bjoc.9.161

• pyroglutamic acid derivative 13 as a single stereoisomer (Scheme 3). Conclusion In this study, we investigated the cis- and trans-stereoselective radical additions to α-methylene-γ-alkyl- γ-lactams. Strong cis-selectivities were observed using various γ-substituents under non-chelating conditions. The

• acid derivative; radical alkylation; Introduction γ-Lactams exist in many natural products and biologically active compounds and are one of the most important classes of compounds for drug discovery [1][2][3]. Substituted γ-lactams, in particular, have potential application in drug synthesis, but the

• the reaction were also revealed. This stereoselective radical reaction was used for synthesis of chiral pyroglutamic acid derivatives starting from a commercially available chiral amino acid. Keywords: chelation controlled reaction; diastereoselective reaction; free radical; lactams; pyroglutamic

Reactions of glycidyl derivatives with ambident nucleophiles; part 2: amino acid derivatives

• Gerald Dyker,
• Andreas Thöne and
• Gerald Henkel

Beilstein J. Org. Chem. 2007, 3, No. 28, doi:10.1186/1860-5397-3-28

• multifunctionalized heterocycles from a pyroglutamic acid derivative, glycidyl components and anilines by nucleophilic substitution and cobalt catalysis is presented. Introduction Recently we investigated the formation of 5- and 6-membered heterocycles from ethyl acetoacetate and glycidyl derivatives such as

• in THF, or potassium carbonate in DMF) these glycidyl esters gave no defined cyclization products, although related reactions have some precedent (for instance cyclization of urethanes of glycidol).[7] For the synthesis of products of type 3b we decided to use the pyroglutamic acid derivative 5 as