Ketimines 1-alkenylation

Similarly, ketimines (benzylimines of aromatic ketones) undergo the rhodium-catalyzed ortho-alkenylation with alkynes to give or/ o-alkenylated aromatic ketones after hydrolysis.61 This method is applied to an efficient one-pot synthesis of isoquinoline derivatives by using aromatic ketones, benzylamine, and alkynes under Rh catalysis (Equation (55)). 

Intramolecular process with rhodium catalyst has been described for the syntheses of indane, dihydroindoles, dihydrofurans, tetralins, and other polycyclic compounds. Wilkinson catalyst is efficient for the cyclization of aromatic ketimines and aldimines containing alkenyl groups tethered to the K z-position of the imine-directing group. 

Ketimines containing a hydrogen atom adjacent to the C=NH group form alkenyl isocyanates upon treatment with phosgene [1772] ... 

Unlike the 4-alkenyl/CO system, the following two cyclization systems, based on C-N double bonds, are completely selective and favor a five-membered ring (Scheme 8). Fallis and Brinza who used a diphenylhydrazone derivative as an acyl radical trap [32] reported the first example in this series. As shown in the first two examples in Table 3, radical carbonylation gave 2-hydrazinocyclopentanones in good yields. Ryu, Komatsu and coworkers reported acyl radical cyclization onto N C double bond, which proceeds exclusively in a 5-exo manner to give pyrrolidi-nones in good yield (runs 3-5) [33]. For an aromatic substrate, it is necessary to use a ketimine rather than an aldimine, since aromatic radical abstracts an imine hy-... 

Ellman, Bergman, and coworker reported a rhodium-catalyzed procedure for the synthesis of pyridines from alkynes and a,/ -unsaturated N-benzyl aldimines and ketimines in 2008 [107]. The reaction proceeded via C-H alkenylation/electrocyclization/aromatization sequence through dihydropyridine intermediates. The C-H activated complex was isolated and determination by X-ray analysis. Good yields of highly substituted pyridines were produced in one-pot manner (Scheme 3.50). 

A -Phosphinoyl and A -thiophosphinoyl ketimines, Ph-C(Me)=N-P(=X)Ph2 (X = O and S), have been hydrophosphonylated in high yield and ee using a copper(I) catalyst liganded with a chiral diphosphino ethane. In the case of the sulfur substrates, facile differentiated removal of the t/imphosphinoyl group affords a-amino phosphonic acid derivatives, Ph- C(Me)(NH2)-P(=0)(0Et)2, that is, phosphonic acid analogues of enantio-enriched a,a-disubstituted a-amino acids. The reaction also accommodates alkyl, cycloalkyl and alkenyl substituents in place of the phenyl. 

In an analogue of the Peterson reaction, lithiated 2-(trimethylsilyl-methyl)pyridine (26) reacts with -aromatic aldimines to give -2-alkenyl-pyridines in high yield and with high stereoselectivity (greater than 99.5% E-configuration). Ketimines and aliphatic imines give much lower yields. ... 

Lim S-G, Lee JH, Moon CW, Hong J-B, Jun C-H (2003) Rh(I)-catalyzed direct ortho-alkenylation of aromatic ketimines with alkynes and its application to the synthesis of isoquinoline dtnivatives. Org Lett 5(15) 2759-2761... 

In the review period, most syntheses of phosphonic acids and their derivatives involved simple organophosphorus reagents, like diallq l and trialkyl phosphites that were widely used in reactions with aHqmes and alkenes including bromoalkenes to obtain alkenyl and allqmylphospo-nates as well as with imines, ketimines, ketones, aldehydes and nitriles to afford imino- and aminophosphonates, and hydroxyphosphonates. Two or more component reactions were also utilised in these syntheses. 

Jun et al. demonstrated a Rh(I)-catalyzed cyclization of an N-benzyl aromatic ketimine with diphenylacetylene to provide isoquinoline 44 [27]. The chelation-assisted C-H activation strategy was employed for the first time for isoquinoline synthesis. However, the reaction required a high temperature (150 C) and led to two different isoquinoline derivatives 44 and 44. Based on the experimental results, the authors proposed a plausible reaction mechanism that involved ortho-alkenylation, 6. r-electrocyclization, intermolecular nucleophilic substitution, and dehydrogenative aromatization (Eq. (5.43)). 

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