Alkylation Of Imines Research Articles

.beta.-Lactams. 1. Highly diastereoselective alkylation of 4-acetoxyazetidin-2-one useful for 1.beta.-methylcarbapenem synthesis

On the basis of the principle of hard and soft acids and bases, a highly diastereoselective «asymmetric soft acid-soft base imine alkylation» was developed. 4-Acetoxyazetidin-2-one (5) was alkylated with the tin(II) enolates of 3-acyl-(4S)-ethyl(and isopropyl)-1,3-thiazolidine-2-thiones 7a,b and 21a,b. The resultant alkylation products (9a,b and 24a,b) could be converted to 17, the key intermediate for the syntheses of both thienamycin (2) and imipenem (3), and to 35, the key intermediate for the synthesis of 1β-methylcarbapenem

ChemInform Abstract: Enamine Chemistry. Part 36. Alkylation of Imines of Medium‐Large Ring Ketones with Electrophilic Alkenes.

AbstractThe course of the alkylation of (I) with alkenes such as (II) is sensitive to the ring size yielding mono‐2‐substituted compounds such as (III).

Enamine chemistry. Part 36. Alkylation of imines of medium–large ring ketones with electrophilic alkenes

The alkylation of the benzylamine imines of cycloheptanone, cyclo-octanone, and cyclododecanone with acrylonitrile, methyl acrylate, methyl vinyl sulphone, phenyl vinyl ketone, and phenyl vinyl sulphone, has been studied. The course of the reaction is surprisingly sensitive to the size of the ring, the size of any substituent at C-2, and the relative reactivity of the electrophilic alkene. Only mono-2-substituted cycloalkanones were produced with all electrophilic alkenes except methyl acrylate, which reacted twice with cycloheptanone imine and, under forcing conditions, twice with, cyclo-octanone imine, to give 2,2-bis-β-methoxycarbonylethylcycloheptanone and 2,8-bis-β-methoxycarbonylethylcyclo-octanone, the latter in very low yield. Methylcycloheptanone imine gave the 2-alkylated-2-methyl ketone with acrylonitrile and methyl acrylate whereas 2-methylcyclododecanone imine gave a mixture of 2-alkylated-2-methyl- and 12-alkylated-2-methyl ketones.

The alkylation of α-ethoxycarbamates with organo-lead, -zinc, and -copper reagents. High cram selectivity and formal nonbasic alkylation of imines

The alkylation of α-ethoxycarbamates is accomplished with organo-lead, -zinc, and -copper reagents in the presence of Lewis acids. The reaction proceeds with high diastereoselectivity in good to high yields.

An efficient asymmetric spiroannulation process

After hydrolytic work-up, intramolecular Michael-type alkylation of imine 11 gave spiro adduct 13 with a high degree of control of the two newly created asymmetric centers.

Complex bases. XIV. Use of sodamide containing complex bases as versatile, inexpensive reagents to generate carbanions

It is shown that Complex Bases NaNH 2-RONa are very efficient in carbanion preparations and allow alkylation of imines, aldehydes, 1,3-dithianes, dithioketals as well as methylsulfenylation of ketones.

Potassium-graphite as a metalation reagent. Synthesis of aldehydes and ketones by alkylation of imines and dihydro-1,3-oxazine

Potassium-graphite as a metalation reagent. Synthesis of aldehydes and ketones by alkylation of imines and dihydro-1,3-oxazine

Chemistry of esters of keto acids of the acetylene series. X. Addition of amines to 3-phenylethynyl-1-quinoxalone

The reaction of 3-phenylethynyl-2-quinoxalones with aliphatic and aromatic amines gives alkyl(aryl)imines of 3-phenacylidene-2-quinoxalone, the structures of which were proved by alternative synthesis from 3-phenacylidene-2-quinoxalone and the appropriate amines.

Reductive alkylation of imines and esters with sodium in ammonia

Reductive alkylation of imines and esters with sodium in ammonia

Formation of enamines by alkylation of imines

cf. CA 64, 12473c. With ice-cooling, 1 equiv. alkylating agent was added to one equiv. of the imine in 1M soln. in a solvent in the presence of NaH to give both N- and C-alkylated products. The following summarizes the date (imine, solvent, alkylating agent, % unreacted imine, % N-alkylated product, % C-alkylated product, % polyalkyl product): PhMeC:NH (I), (EtOCH2)2 (II), Et3OBF4 (III), 8, 88, 4, -; I, II, Et2SO4, 9, 49, 42, -; I, II, EtI (IV), 5, 5, 90, -. In the following, NaNH2 replaced NaH (same data given): cyclohexanon imine (V), hexamethylphosphoric triamide (VI), III, 29, 53, 18, -; V, VI, Me2SO4 (VIa), 11, 75, 10, 4; V, VI, IV, 15, 17, 56, 12; Et2C:NH (VII), VI, III, 26, 29, 42, 3; VII, VI, VIa, 17, 57, 26, 0; and VII, VI, IV, 20, 0, 71, 9. [on SciFinder (R)]