Cyclic Sulfamidates as Vehicles for the Synthesis of Substituted Lactams

Abstract

[reaction: see text] A structurally diverse series of mono- and disubstituted 1,2- and 1,3-cyclic sulfamidates react with stabilized enolates, including malonate and phosphonoacetate variants, to provide, after lactamization, substituted and alpha-functionalized pyrrolidinone and piperidinone derivatives.

Stereoselective Total Synthesis of Tubulysin V

“…The chiral amino group in compound 7 was introduced through zinc-mediated aza-Barbier reaction between N-tert-butanesulfinyl imine 8 derived from phenylacetaldehyde and allylic bromide 9. [8] The optical purity of compound 7 could be enriched to 99% de after single recrystallization using CH 2 Cl 2 /Et 2 O as co-solvent. not only significantly accelerated the reaction, but also improved the diastereo-selectivity.…”

Recent Advances in the Synthesis of α‐Alkylidene‐Substituted δ‐Lactones, γ‐Lactams and δ‐Lactams

“…Scheme 24. Another interesting method, employing organophosphorus reagents for the synthesis of the N-substituted α-alkylidene γ-lactams 118 (Scheme 25), was developed by Gallagher and co-workers. [37] As the key step the approach utilized ring opening of the cyclic sulfonamidates 115 with carbanions generated from the ethyl (dialkoxyphosphoryl)-acetates 113. Thermal lactamization of the initially formed products 116 after loss of SO 3 gave the corresponding α-(diethoxyphosphoryl) γ-lactams 117 as mixtures of two epimers at the C-3 stereogenic centre.…”

Enantioselective Access to Chiral Cyclic Sulfamidates Through Iridium‐Catalyzed Asymmetric Hydrogenation

“…Chiral cyclic sulfamidates are versatile intermediates for the construction of some important chemical and biological molecules. [1][2][3] For example, they have wide range of application to work as potential precursors for the synthesis of chiral amines, amino alcohols and amino acids through various synthetic transformations. [2][3] Taking into account of their great synthetic importance, much attention has been paid to the development of highly efficient synthetic methodologies.…”

“…To explore the feasibility of Ir-catalyzed asymmetric hydrogenation of cyclic sulfamidate imines, 4phenyl-5H- [1,2,3] bisphosphine ligands ( Figure 1). As shown in Table 1, several bisphosphine-(thio)urea ligands L1-L3 were applied in this Ir-catalyzed asymmetric hydrogenation ( Table 1, entries 1-3).…”

“…The 2-napthyl (1 n) and heteroaromatic (1 o) substrates worked well to provide the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 desired products (2 n-2 o) with excellent results (> 99% conversion, 97%-98% yields, 96%-97% ee). In addition, the alkyl substrate 4-benzyl-5H- [1,2,3]-oxathiazole 2,2-dioxide (1 p) could also be hydrogenated smoothly to achieve full conversion, high yield and moderate enantioselectivity (98% yield and 73% ee).…”