Recent progress on catalytic [1,3]-oxygen rearrangement reactions from nitrogen to carbon atoms

Sequential Acylation/Silylation/Hetero‐Claisen Rearrangement of Nitroalkanes for the Synthesis of Protected Hydroxyoxime Derivatives

“…If concerted, uncatalyzed [1,3]sigmatropic rearrangement should have high barrier due to the orbital symmetry rules. [16] If ionic, cation C possessing O-silyl group should be more stable than cation D possessing more accepting O-acyl group, as well as carboxylate anion (formed simultaneously with C) is more stable than silanolate anion. These also makes [3,3]-rearrangement a preferable route (Scheme 10).…”

“…Indeed [3,3]‐rearrangement of 4 should be preferable regardless of concerted or ionic pathway. If concerted, uncatalyzed [1,3]‐sigmatropic rearrangement should have high barrier due to the orbital symmetry rules [16] . If ionic, cation C possessing O ‐silyl group should be more stable than cation D possessing more accepting O ‐acyl group, as well as carboxylate anion (formed simultaneously with C ) is more stable than silanolate anion.…”

Radical boron migration of allylboronic esters

“…35 On the contrary, the analogous 1,3-shift process has encountered inevitable difficulties because of the disfavored four-membered cyclic transition state and no example of γ-boron migration has been reported. [36][37][38][39][40][41][42] Theoretical studies on such 1,3-boron migrating process has been concluded thermodynamically infavorable and experimentally inaccessible. 43 We envisioned that through consecutive boron-walking on carbon skeleton, the boronic ester moiety could switch to remote end of the allylic backbones for the formation of more stablized radical intermediates.…”

Recent advances in catalytic asymmetric [1,3]-rearrangement reactions

“…3–6 Under harsh reaction conditions, substrates require highly distorted transition states to transform in an antarafacial manner. 7–11 Compared with the [3,3]-rearrangement, the structure of the transition state and the configuration of the products in the [1,3]-rearrangement are difficult to control whether the rearrangement is a concerted or stepwise process. The issues arising from the balance of reactivity and stereoselectivity are frequently encountered, thereby posing restrictions on the development of an asymmetric [1,3]-rearrangement.…”