Construction of nitrogen-heterocyclic compounds through zirconium mediated intramolecular alkene-carbonyl coupling reaction of N-(o-alkenylaryl)carbamate derivatives

Iron‐Catalyzed Reductive Cyclization by Hydromagnesiation: A Modular Strategy Towards N‐Heterocycles

“…In comparison to indoles, higher temperatures and increased reaction times were needed to obtain the oxindole products 4 in fair yields. It should be noted that a related strategy was previously described by Taguchi, but was a non‐catalyzed process requiring excess pre‐formed Negishi reagent [26] …”

“…In comparison to indoles, higher temperatures and increased reaction times were needed to obtain the oxindole products 4 in fair yields.I t should be noted that ar elated strategy was previously described by Taguchi, but was an on-catalyzed process requiring excess pre-formed Negishi reagent. [26] Additionally,the putative intermediate I could be trapped with external electrophiles in ao ne-pot process to access oxindoles bearing all-carbon quaternary centers (Scheme 3b). It is noteworthy that this process represents af ormal 1,1-dicarbofunctionalization of the styrene moiety.…”

Formation of Optically Pure Cyclic Amines by Intramolecular Conjugate Displacement

“…This was protected as its carbamate (Boc 2 O) and then subjected to a Stille coupling to install the vinyl group ( 23b → 23c → 23d ). N -Benzylation, conversion to the triisopropylsilyl carbamate 23f , and double bond cleavage (OsO 4 , NaIO 4 ) led to 23 . We had first carried out the Stille coupling after N -benzylation, but the route shown in Scheme is better, as some of the intermediates are easier to purify.…”

Diastereoselective Intramolecular Ester Transfer Reaction ofN-Alkenylcar­bamate Derivatives Mediated by Zirconocene-Butene Complex: Preparation of α,γ-Disubstituted γ-Aminobutyric Acid (GABA) Derivatives and 2,4-Di­substituted Pyrrolidine Derivatives

“…1 We have recently demonstrated successful examples of zirconium mediated intramolecular alkene-carbonyl coupling reaction of tert-butyl N-alkenyl-N-sulfonylcarbamate derivatives to give ester group transferred product (Scheme 1). 11,12 We have also clarified the reaction pathway on the basis of the observed stereospecificities in the iodination reactions of the reaction intermediates formed from both E-and Z-isomer of 3-akenylcarbamate derivatives. 11 As shown in Scheme 1 the reaction pathway can be simply illustrated using 3-butenylcarbamate derivative 1a.…”