| Abstract
| - The Rh2(OAc)4-stabilized carbenoid derived from dimethyl diazomalonate has been found to insertinto the N−H bond of sterically hindered secondary aliphatic amines to afford hindered tertiaryaliphatic amines in quite satisfactory yields. For example dimethyl 2-(dicyclohexylamino)propanedioate was formed in 85% yield from dicyclohexylamine, and the severely hindered dimethyl2-(2,2,6,6-tetramethyl-1-piperidinyl)propanedioate was formed in 38% yield from 2,2,6,6-tetramethylpiperidine. The Rh2(OAc)4 - dimethyl diazomalonate reaction was found to work also forarylalkylamines and diarylamines. In these cases, small amounts of products resulting from formalinsertion of the carbenoid into an aromatic C−H bond were detected. Substitution at ortho positionscaused the yield of C−H insertion products to increase. Other diazo compounds, viz. ethyldiazoacetoacetate, 2-diazocyclohexane-1,3-dione, and 2-diazo-5,5-dimethylcyclohexane-1,3-dione,performed satisfactorily in Rh2(OAc)4-catalyzed reactions with arylalkylamines and diarylamines,but led to complicated reaction mixtures with dialkylamines.
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