/pdf/extension-of-hydrogen-borrowing-alkylation-reactions-for-the-3nroxbbz.pdf

Extension of hydrogen borrowing alkylation reactions for the total synthesis of (-)-γ-lycorane.

Total synthesis of (+)-γ-lycorane from ethyl lactate using iterative Claisen and Overman rearrangement reactions

Catalytic, Asymmetric Total Synthesis of (+)-α-, (+)-β-, (+)-γ-, and (-)-δ-Lycorane.

TFA promoted deprotection of O-Ts activated N-Boc hydroxylamines triggers aminofunctionalization-based polycyclizations of tethered alkenes. The processes involve intramolecular stereospecific aza-Prilezhaev alkene aziridination in advance of stereospecific C-N cleavage by a pendant nucleophile. Using this approach, a wide range of fully intramolecular alkene anti-1,2-difunctionalizations can be achieved, including diaminations, amino-oxygenations and amino-arylations. Trends associated with the regioselectivity of the C-N cleavage step are outlined. The method provides a broad and predictable platform for accessing diverse C(sp3)-rich polyheterocycles of relevance to medicinal chemistry.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/anie.202301262

A Stereospecific Alkene 1,2-Aminofunctionalization Platform for the Assembly of Complex Nitrogen Containing Ring Systems.

TFA promoted deprotection of O−Ts activated N-Boc hydroxylamines triggers aminofunctionalization-based polycyclizations of tethered alkenes. The processes involve intramolecular stereospecific aza-Prilezhaev alkene aziridination in advance of stereospecific C−N cleavage by a pendant nucleophile. Using this approach, a wide range of fully intramolecular alkene anti-1,2-difunctionalizations can be achieved, including diaminations, amino-oxygenations and amino-arylations. Trends associated with the regioselectivity of the C−N cleavage step are outlined. The method provides a broad and predictable platform for accessing diverse C(sp3)-rich polyheterocycles of relevance to medicinal chemistry. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/ange.202301262

A Stereospecific Alkene 1,2‐Aminofunctionalization Platform for the Assembly of Complex Nitrogen‐Containing Ring Systems

A concise total synthesis of (−)-γ-lycorane via an aromatic CH alkylation of unactivated secondary alkyl iodide

The invention discloses a synthesis method of an intermediate for preparing cephalotaxine. Cyclopentadienylsodium and methyl 3-bromopropionate which are taken as initial raw materials undergo six steps of reactions including nucleophilic addition, hydroboration oxidation, hydroxyl protection, reduction, oxidation and reductive ammoniation to synthesize N-2-(3,4-methylenedioxyphenethyl)-3-(4-methoxymethyl-1-cyclopentenyl-1-propyl)amine. The method can be used as a brand-new synthesis route of the intermediate, and has the advantages of mild reaction conditions, simplicity in operation, cheap and easily available raw materials, and high reaction yield, and experimental verification shows that the total yield of the method can reach 33.4%. In conclusion, the method fills the gap in synthesismethods of the N-2-(3,4-methylenedioxyphenethyl)-3-(4-methoxymethyl-1-cyclopentenyl-1-propyl)amine, and has outstanding technical advantages in the aspects of cost, yield, reaction conditions and thelike.

Synthesis method of intermediate for preparing cephalotaxine

The invention discloses a novel method for synthesizing entecavir. The novel method takes a compound with a known formula 9 as a starting raw material, and a target molecule is synthesized through a series of reactions including a Morita-Baylis-Hillman reaction, a Sharpless asymmetric epoxidation reaction, TBSCl hydroxyl protection, an opening epoxidation reaction, TBSCl hydroxyl protection, a step of reducing carbonyl into double bonds, SeO2 one-step oxidization double-bond alpha-site H ketone formation reaction, a step of reducing ketone into hydroxyl through lithium triethylborohydride andthe like. The design of a whole route is unique and novel; a reaction process has mild reaction conditions and a rapid speed; side reactions are relatively few and the operation is simple and convenient; conventional chemical reagents are utilized in the route; the raw material is cheap and easy to obtain and the synthesis cost can be greatly reduced.

Zhang Xuesong

Papers

A concise total synthesis of (−)-γ-lycorane via an aromatic CH alkylation of unactivated secondary alkyl iodide

Synthesis method of intermediate for preparing cephalotaxine

Novel synthesis method of hepatitis B treating medicine entecavir