A method is described of joining the 2-oxo-butyl group to a ketone. The sequence is illustrated by the synthesis of dihydro-β-ionone (2) from 2,2,6-trimethylcyclohexanone (1).

A new synthesis is reported of polyalkyltetralones based on reactions of a,a-dialkylarylacyl chlorides with branched alkenes in the presence of stannic chloride. The following were synthesized by this method: 1,1,4,4-tetramethyl-2-tetralone (7a), 1 ,I ,3,4,4-pentamethyl-2-tetralone (7b), 1,1,4,4,6-pentamethyl-2-tetralone (7c), 1,l-diethyl-4,4-dimethyl-2-tetralone (7d), and 3-keto-l,l,4,4-tetramethyl-1,2,3,4-tetrahydrophenanthrene (7e). Cyclialkylation of toluene with 2,2,5,5-tetramethyltetrahydrofuranone yielded 1,1,4,4,7-pentamethyl-2-tetralone. Monobromoderivatives were prepared from ketones 7a, b, and e and dibromoderivatives from ketones 7a and e. The polyalkyltetralones are used as intermediates in the synthesis of ortho-diquaternary aromatic compounds by various oxidative procedures.

The ketones 1,1,4,4-tetramethyl-2-tetralone ( l a ) , 1,1,4,4,7-penlamethyl-2-tetralone ( l b ) , and 1,1,4,4,6-pentamethyl-2-tetralone ( l c ) undergo rearrangement on heating with aluminum chloride or ferric chloride in tetrachloroethane or nitromethane into mixtures of their respective isomeric ketones, I-acetyl-1,3,3-trimethylindane (2a) and 2,2,4,4-tetramethyl-l-tetralone (3a) from l a , 1-acetyl-l,3,3,6-tetramethylindane (26) and 2,2,4,4,7-pentamethyl-I-tetralone (36) from 16, and I-acetyl-l,3,3,5-tetramethylindane (2c) and 2,2,4,4,6-pentamethyl-1-tetralone (3c) from l c . A quantitative study using g.1.c. of the distribution of the ketones with time shows that the sequence of the rearrangement is: 1 F? 2 -> 3. A methyl group homologously para to the carbonyl ( l c ) accelerates the rearrangement. The same kind of rearrangement takes place during Friedel-Crafts cyclialkylation with 2,2,5,5-tetramethyltetrahydrofuranone. A unifying reaction mechanism is postulated to account for the rearrangements. This mechanism also accounts for the rearrangement and fragmentation products from treatment of 1,1,4,4-tetramethyl-2,3-dioxotetralin ( 9 ) with aluminum chloride or sulfuric-acetic acids. The products from 9 include l-acetyl-1,3,3-trimethyl-2-indanone, 1,1,3-trimethyl-2-indanone, and, from the aluminum chloride -catalyzed rearrangement, 5(or 6)-acetyl-1,1,3-trimethyl-2-indanone.Les citones titramithyl-1,1,4,4 titralone-2 ( l a ) pentamithyl-l,l,4,4,7 titralone-2 (16) et pentamkthyl-1,1,4,4,6 tetralone-2 ( l c ) se riarrangement par chauffage en presence de chlorure d'aluminium ou chlorure ferrique dans le tCtrachloroethane ou nitromithane, en milange de leurs citones isomeres respectivement acityl-1 trimethyl-1,3,3 indane (2n) et tetramithyl-2,2,4,4 tetralone-l (30) a partir de I n ; acetyl-1 tetramethyl-1,3,3,6 indane (26) et pentamethyl-2,2,4,4,7 tetralone-l (36) a partir de 16 et acityl-1 tetramethyl-1,3,3,5 indane (2c) et pentamethyl-2,2,4,4,6 tetralone-1 (3c) a partir de l c . Une etude quantitative par c.g.1. de la distribution des citones en fonction du temps, montre qile la sequence du rearrangement est: 1 F? 2 -> 3. Un groupe methyle hon~ologue en para du carbonyl ( l c ) accklere le rearrangement. Le m&me type de rearrangement a lieu lors de la cycloalkylation selon Friedel et Crafts de la tetramethyl-7, 2,5,5 tetrahydrofuranone. Un mecanisme reactionnel a ete posti~li pour expliquer ces rearrangements. Ce micanisme tient compte Cgalement des produits de rearrangement et de fragmentation lors du traitement de la tetramethyl-1,1,4,4 dioxo-2,3 titraline ( 9 ) par la chlorure d'aluminium ou le melange d'acides sulfurique-acetique. Les produits issus de 9 comprennent I'acCtyl-1 trimethyl-1,3,3 indanone-2, la trimethyl-1,1,3 indanone-2 et, a partir du rearrangement catalysk par AICI,, I'acetyl-5 (ou 6) trinlithyl-

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In Tetrachloräthan oder Nitromethan und in Gegenwart von Al‐ oder Fe‐chlorid lagern sich die Ketone (I) in der Wärme zu den Indanen (II) und den Tetralonen (III) um.