The t-Amino Effect: Heterocycles Formed by Ring Closure of ortho-Substituted t-Anilines**Dedicated to my evergreen friend and mentor, Professor Hans Suschitzky, on his 80th birthday.

Theoretical Studies of the Asymmetric Binary‐Acid‐Catalyzed tert‐Aminocyclization Reaction: Origins of the CH Activation and Stereoselectivity

“…The direct CÀH bond-activation strategy based on the "tertamino" effect is a powerful method for the functionalization of relatively inert C À H bonds. [1] In this field, the intramolecular tert-aminocyclization reaction, which is a highly atom-/ redox-economic process, represents an intriguing cascade C sp 3 À H-activation/C À X-formation process for the synthesis of heterocyclic compounds, especially for the synthesis of tetrahydroquinoline derivatives. [2] Recently, this traditionally thermal process was found to work under catalytic conditions; both Lewis acids and Brønsted acids were able to trigger this reaction.…”

“…Generally speaking, the reaction involves a rate-limiting 1,5-H transfer and subsequent stereochemistry-generating C À X bond formation steps. [1,2] Previously, the thermally triggered tert-aminocyclization reac-tion has been systematically studied by Reinhoudt and coworkers, [8] who found that the 1,5-H-transfer step occurred stereospecifically in a 1,5-suprafacial manner. Moreover, they suggested that the as-formed carbanion would add onto the iminium double bond from the side on which the hydrogen is transferred.…”

Tri- and Tetracyclic Azepine Derivatives by Thermally Induced Cyclization of Aminoallenes and Semicyclic 2-Dienamines

“…The term “ tert -amino effect” was originally assigned to this category of reactions by Suschitzky and Meth-Cohn . More recently, Viehe introduced the more descriptive term “α-cyclization of tertiary amines.” Reactions of this type were first observed for tertiary anilines bearing in ortho position a double-bond function with at least one heteroatom 1 ( I , ab: NO, NO 2 , NNR, CNR, CN + R 2 , CO), but it was later realized that the ortho substituent could also be an acceptor-substituted vinyl group.…”

Organocatalytic C–H activation reactions

“…tert- Amino effect: The “ tert -amino effect” refers to the ring-closure reactions that proceed by redox processes for C–C and C–X bond formation within conjugated systems [7–9]. One well-known example of the “ tert -amino effect” is the cyclization of N , N -dialkyl-substituted anilines with imines to generate cyclic aminals.…”