Self-annulment

The Saigo group disclosed the first highly enantioselective self-annulation of enals catalyzed by the cyclophane-type chiral NHC to afford y-butyro-lactones (91-99% ee for the trans isomers). a,a,a-Trifluoroacetophenone... 

Scheme 7.36 NHC-catalyzed asymmetric self-annulation of enals reported by Saigo.

Bryce and co-workers reported that the crown-annulated TTF derivatives 98 and 99 were used for UV-Vis spectroscopic and electrochemical studies of metal complexation <1996J(P2)1587>. Solution electrochemical studies showed that metal complexation to the crown unit leads to a small anodic shift in the first oxidation potential of the TTF system. Langmuir-Blodgett films of amphiphilic 99 have been assembled on solid substrates by Y-type deposition. Compounds 100-104 were used to prepare self-assembled monolayers on gold and platinum surfaces <1998AM395, 2000JOC8269>. The self-assembled monolayers of 104 were the most stable in this series of TTF-crowns. Electrochemical data for the self-assembled monolayers of 100-104 in MeCN showed two reversible one-electron waves, typical of the TTF system. The self-assembled monolayers of 102-104 exhibited an electrochemical response in aqueous electrolyes, which was observed between 50 and 100 cycles. 

Aldol reactions. Self-condensation of aldehydes as well as Robinson annulation are effected. The latter process is conducted in the presence of molecular sieves 4A in aprotic solvents such as toluene. 

Two Nitrogen Atoms (it is self-subdivided into Pyrazoles, Imidazoles, and Annulated Imidazoles). 

One Nitrogen Atom (it is self-subdivided into Pyridines, Pyridinium Compounds, Ylides, Pyridine N-Oxides, Applications of Pyridines, Bipyridines and Related Systems, Hydropyridines, Biologically Active Pyridines and Hydropyridines, Pyridines Annulated with Carbocycles, Pyridines Annulated with Heterocycles). 

Two Nitrogen Atoms (it is self-sub divided into 1,2-Heterocycles, 1,3-Heterocycles Monocyclic Pyrimidines and Hydropyrimidines Except Pyrimidine Nucleoside Bases and Nucleosides, Annulated Pyrimidines Except Purines, Pteridines, and Flavins, Pyrimidine Nucleoside Bases and Purines, Nucleotides and Nucleosides, Nucleic Acids, Pyrazines, and Hydropyrazines). 

In short, the term psychiatric disorder is useful because it enables psychiatrists to waffle It may be a disease, or may not be may render the patient incompetent, or may not may annul intentionality, but not necessarily may cause dangerousness to self and others, but not always and be an excuse for crime, and may not be. It all depends on the psychiatrists interpretation of their so-called clinical observations. This discretion enables them—aided and abetted by other physicians, lawyers, politicians, journalists, and the general public—to transform personal, marital, moral, political, social, and spiritual problems into mental diseases. 

Decision on the Annulment of the Illegitimate Acts of the Provisional Institutions of Self-government in Kosovo and Metohija on their Declaration of Unilateral Independence, undated. Text available at http //en.wikisource.org/wiki/Decision on the annulment of the iUegitimate acts of the provisional institutions of self-government in Kosovo and Metohija on their declaration of unilateral indepen dence, accessed 3 November 2008. 

A classical reaction of an enolate anion with a conjugated carbonyl leads to a bicyclic derivative. When cyclohexanone (58) is heated with methyl vinyl ketone (10) in the presence of ethanoUc KOH, the final product (after hydrolysis) is bicyclic ketone 64. This process is called the Robinson annulation, after Sir Robert Robinson (England 1886-1975). It begins with the reaction of 58 with KOH to form the enolate anion (59). Under these conditions, Michael addition to 10 is faster than self-condensation of the ketone (see Chapter 22, Section 22.2), and the product is enolate anion 60. 

Substituted benzaldehydes can be self-coupled oxidatively to give C(3)-substituted phthalides (146), using a rhodium(III)/aniline dual catalysis. The cascade ortho-C-M- (g) activation/insertion/annulation sequence can also be used in a heterocoupling sense with a second aldehyde. The dual catalysis allows plenty of scope for generating an enantios-elective version. 

Very recently, Wu and co-workers achieved a novel l2-mediated Radziszewski-type reaction of methyl ketones 8, anilines 9, and tosylmethyl isocyanide (TosMlC) 10 via [2 + 1+1 + 1] annulations for the assembly of 1,2,5-trisubstituted imidazoles 11 (Scheme 7.5) [60]. In this protocol, the methylketones 8 play dual roles as a-dicarbonyl compounds and aldehydes for the first time. Initial studies of the mechanism suggest that the reaction proceeds via a key C-acyfimine intermediate and I2 plays an important role in the self-sorting tandem reaction. 

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