P-enamino amides

Benovsky P, Stephenson GA, Stille JR (1998) Asymmetric formation of quaternary centers through aza-annulation of chiral P-enamino amides with acrylate derivatives. J Am Chem Soc 120 2493-2500... 

Section 4.1 Vinylogous Amides p-Enamino Ketones Section 4.2 Vinylogous Carbamates [S-Enamino Esters Section 4.3 Vinylogous Ureas P-Enamino Amides... 

The use of aza-annulation reagent 347 was also applied to the reaction with p-enamino amide substrates (eq. 76).9 Treatment of 379 with 347 led to formation of the A-substituted and A-unsubstituted amino acid derivatives 380, and the unsubstituted substrate produced superior yields. 

Highly Enantioselective Hydrogenation of Unprotected P-Enamino Amides and the Use of Josiphos-Ligands... 

Oxidation. P-Enamino carboxamides derived from cyclic p-keto amides are oxidized by Mn(OAc)j-Cu(OAc)2 to give enones, dienamines, or aniline derivatives, depending on the ring size. 

Quaternary stereocenters can be obtained with high selectivity with ot-amino acid amides as chiral auxiliaries, which were first converted with P-oxo esters to give enamines such as compounds 58. According to a combinatorial strategy, various enamino esters 58 were screened in Michael additions with MVK (41a) and several metal salts as catalysts. With FeCl3, however, the maximum stereoselectivity achieved was only 77% ee (with enamine 58a derived from L-isoleucine dimethylamide). Cu(0Ac)2H20 turned out be the optimal catalyst for this transformation. With L-valine diethylamide as chiral auxiliary in compound 58b, reaction proceeds with 86% yield and 98% ee after aqueous workup [79]. Importantly, this valuable method for the construction of quaternary stereocenters [80] under ambient conditions seems to be generally applicable to a number of Michael donors [81]. In all cases, the auxiliary can be quantitatively recovered after workup. 

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