Highly stereoselective intramolecular Buchner reaction of diazoacetamides catalyzed by a Ru(ii)–Pheox complex

Abstract

This work reports the first efficient enantioselective intramolecular Buchner reaction of diazoacetamides.

Skeletal Editing of (Hetero)Arenes Using Carbenes

“…The results demonstrated that using bulky ligands in the rhodium‐catalyzed reaction increased reactivity towards C−H insertion to yield β‐lactam product, whereas silver‐ and copper‐catalyzed reactions activated intramolecular Buchner cyclization (Scheme 24b) [115] . The enantiocontrol of the intramolecular Buchner reaction for the generation of tertiary stereogenic centers improved by using cationic chiral Ru‐complex [116] . Very recently, Darses et al.…”

“…[115] The enantiocontrol of the intramolecular Buchner reaction for the generation of tertiary stereogenic centers improved by using cationic chiral Ru-complex. [116] Very recently, Darses et al Chemistry-A European Journal achieved the efficient synthesis of enantioenriched cycloheptatrienes through catalytic asymmetric intramolecular Buchner reaction using cyano-substituted diazo derivatives. Their DFT calculations revealed the stereochemical coexistence of norcaradiene and cycloheptatriene valence isomers at the solid state (Scheme 24c).…”

Uncommon carbene insertion reactions

“…Iwasa et al 64 reported a highly enantioselective intramolecular Buchner reaction of diazoacetamides by using Ru( ii )–Pheox as a catalyst, which affords various γ-lactam fused 5,7-bicyclic-heptatriene derivatives in excellent yields and enantioselectivities (up to 99% yield and 99% ee) ( Scheme 16a ). By using β-cyano α-diazoacetamide, Darses et al 65 realized an asymmetric intramolecular Buchner reaction, which allowed the highly stereoselective installation of a quaternary stereogenic center in the 5,7- or 6,7-bicyclic skeletons in the presence of chiral dirhodium catalysts ( Scheme 16b ).…”

Recent advances in transition-metal-catalyzed Büchner reaction of alkynes

“…8 Following this notion, a plethora of efficient synthetic methods have also been developed by Doyle, 9 Merlic, 10 Xu, 11 and others based on this strategy, leading to functionalized seven-membered rings. 12 During the last decade, the chemistry of Büchner reactions has been extensively explored, and numerous reviews have described their applications. 13 However, to our knowledge, no comprehensive review on the transition-metal-catalyzed Büchner reaction of alkynes, especially the involvement of a metal carbene intermediate, is documented.…”