Diastereoselective Intramolecular Hydride Transfer under Brønsted Acid Catalysis

Abstract

A diastereoselective hydride transfer process has been developed under Brønsted acid-catalyzed reaction conditions using methyl ethers or acetals as hydride donors and tertiary alcohols or alkenes as precursors of carbocation. The method enables construction of complex molecules having multiple stereogenic centers from rather simple and readily available starting materials with predictable diastereoselective control.

Diastereoselective Bidirectional C(sp3)−H Bond Functionalization of Piperazine Compounds

“…It is well developed for the construction of C−C, [5] C−O [5b,6] or C−N [7] bonds and offers rapid access to polycyclic compounds. [1,n]‐HT/cyclization occurs under either thermal conditions [7b] or the catalysis of Lewis acids [5c,e,8] and Brønsted acids [5d,7c,9] …”

Triflamides and Triflimides: Synthesis and Applications

“…A number of works can be mentioned in which Tf2NH was successfully used as a catalyst. These include the synthesis of poly-L-lactide in CO2 under plasticization conditions [54], the nucleophilic C-arylation of halopurines leading to N7-substituted pu rine biaryls [55], reactions of the diastereoselective intramolecular hydride shift in the presence of alkenes [56], the preparation of amides from vinyl azides and alcohols [50] Triflimide 1 is used as a catalyst in the isoprenylation of aliphatic aldehydes via the (3,3)-sigmatropic rearrangement of N-Boc-N-(1,1-dimethylallyl)hydrazones [50], in the synthesis of amides from vinyl azides and alcohols [51] and in the rearrangement of N-(1trimethylsilyl)allylhydrazones with the formation of the corresponding vinylsilanes and cyclopropanes [52]. In addition, triflimide activates the silylium catalyst in the reactions of the selective functionalization of azines with the formation of N-silylated dihydropyridines [53].…”

“…A number of works can be mentioned in which Tf 2 NH was successfully used as a catalyst. These include the synthesis of poly-L-lactide in CO 2 under plasticization conditions [54], the nucleophilic C-arylation of halopurines leading to N7-substituted purine biaryls [55], reactions of the diastereoselective intramolecular hydride shift in the presence of alkenes [56], the preparation of amides from vinyl azides and alcohols [50], the synthesis of polysubstituted naphthalenes by the reaction of arylacetaldehydes with alkynes (benzenylation reaction) [57,58], glycosylation reactions [59], three-component regioselective synthesis of tetrahydrofuro [2,3-d]oxazoles [60], etc.…”

Cascade [1,5]-Hydride Transfer/Cyclization for Synthesis of [3,4]-Fused Oxindoles

“…The cascade [1,5]-hydride transfer/cyclization has recently emerged as a powerful tool for the efficient construction of architecturally complex molecules via an intramolecular redox process . In recent decades, organic chemists have developed several hydride acceptors including electron-poor alkene, alkyne, aldehyde, imine, and others to snatch the hydrides adjacent to heteroatoms, with the production of the active carbocation intermediates. Then, the in situ generated carbocation intermediates are captured immediately via intramolecular or intermolecular nucleophilic attack to release the heterocyclic compounds.…”