Synthesis of Saturated Heterocycles

Synthesis of saturated heterocycles 89GSM(11)547 90GSM(12)423 91GSM(13)372 92GSM(14)363 93GSM(15)301. 

General reviews on carbenes and nitrenes in heterocyclic chemistry and on the synthesis of saturated heterocycles have been published this year, and also specific reviews on 1,2-diazepines, 1,2-benzodiazepines, thiepins, dithiepins, and aza-azulenes." ... 

Synthesis of saturated heterocycles via metal-catalyzed formal cycloaddition reactions that generate a C—N or C—O bond 13THC(32)225. Synthesis of saturated heterocycles via metal-catalyzed alkene carboami-nation, carboalkoxylation diamination, aminoalkoxylation, dialkoxyla-tion hydroamination or hydroalkoxylation reactions 13THC(32)1, 13THC(32)39, 13THC(32)109. 

Synthesis of saturated heterocycles via metal-catalyzed allylic alkylation... 

A number of reviews on several aspects of sulphur chemistry and comprehensive books on general organic chemistry include material pertinent to this Report Among these are various chapters of recent volumes of a well-known reference book and of a new comprehensive book on Organic Chemistry. A review on n.m.r. data of non-aromatic heterocyclic compounds includes numerous data on saturated sulphur heterocycles. The synthesis of saturated heterocyclic rings has been summarized. Conformations of five-membered rings have been reviewed in detail. New tellurium heterocyclic chemistry has been summarized. ... 

The aim of this Report is to review new methodology for the synthesis of saturated heterocyclic compounds. Emphasis is placed on reactions which involve a cyclization step and few ring transformations are described. Heterocycles which contain phosphorus, selenium, and silicon as the heteroatom are omitted. A few key steps in complex natural product syntheses are mentioned, but carbohydrates are excluded. The rapidly increasing numbers of reports describing the synthesis of saturated and unsaturated lactones and of crown ethers are covered in Chapters 3 and 10. 

Wolfe JP (2008) Stereoselective synthesis of saturated heterocycles via palladium-catalyzed alkene carhoetherification and carboamination reactions. Synlett 2913-2937... 

This report on General and Synthetic Methods is similar in scope and format to the previous two volumes in the series. Developments in the synthesis of saturated heterocycles, unfortunately omitted from Volume 2, are covered in this volume (Chapter 8), and a special report on Photochemistry in Synthesis (Chapter 10) is included. 

Methods for synthesis of saturated seven-member 0-heterocycles and bicyclic systems with 0-bridge 98ACR603. 

Synthesis of the heterocyclic core possessing a fully saturated six-membered ring can be achieved using a catalytic hydrogenation (see Section 11.10.4.5.5). The six-membered ring can also be formed starting from the appropriate... 

The intramolecular reaction between carbenoids and amides is clearly emerging as a powerful tool for the synthesis of saturated oxazolo[3,2-tf]pyridine derivatives as shown by the cyclization of simple to extremely functionalized substrates 379 <2003CC440> and 381 <20050L47> (Scheme 100) trapping the intermediate isomtinchnone 1,3-dipoles by external (MeOH) or internal (indole) nucleophiles results in new heterocyclic fused systems with especially high efficiency. 

As with the other procedures for the preparation of six-membered heterocyclic systems which proceed via formation of only one ring bond there are relatively few methods which involve formation of a ring bond y to the heteroatom and which can best be classified as [6 + 0] processes rather than [4 + 2], [3 + 3], etc, processes. Of those which can be so represented, however, a number are important processes which are widely used for the synthesis of saturated, partially saturated and aromatic six-membered heterocyclic systems and their benzo derivatives. Mechanistically, the nucleophile —> electrophile approach is by far the most common, but in contrast to the reactions discussed in the previous three sections, radical cyclizations are of considerable utility here. 

Scheme 2.6 Synthesis of saturated and unsaturated group 13-group 15 heterocycles by alkane elimination.

Synthesis of saturated 5-membered heterocycles using organosilicon compounds 92YZ147. 

Synthesis of saturated N- and N,O-heterocycles by addition of nitrogen-containing reagents to alkenylsilanes 92MI38. 

The synthesis of aza-oxa crown ethers is best accomplished by making carbon-nitrogen bonds in the cyclisation step. Although the original syntheses operated under conditions of high dilution and involved the co-condensation of a diamine with a diacid chloride, these methods have been supplanted by the more versatile and convenient A-alkylation pathways involving toluene-sulfonamide or TV-benzyl intermediates. This chapter has focused on the metal-free synthesis of saturated aza-oxa crown ethers. There are a large number of examples of the synthesis of aromatic and heterocyclic aza-oxa crown ethers that involve the co-condensation of aldehydes and amines mediated by metal ions such as Pb2+ and Ba2+24,25 This in situ synthetic... 

Oxidative cyclizations in synthesis of saturated O-heterocycles 80MI40. Polymers including O-heterocyclic fragments, formation by cyclopolymeri-... 

A particularly useful general method for the synthesis of saturated nitrogen- and oxygen-containing partially unsaturated heterocycles, from 5-membered to medium ring-sized, is the Grubbs olefin metathesis applied, for example, to acyclic diaUcenyl-amines, as illustrated by syntheses of a dihydropyrrole and a tetrahydropyridine. ... 

F. G. Mann, working in the field since 1935, is undoubtedly the father of phosphorus as well as arsenic heterocyclic chemistry. Most of his work, mainly on saturated and benzo-annellated ring systems, is summarized in his monograph phosphorus heterocycles were made by K. Issleib and by B. A. Arbuzov, the son of... 

Two further chapters deal with developments in the synthesis of saturated carbocycles (Chapter 7) and saturated heterocycles (Chapter 8) and the final chapter provides a summary of Highlights in Total Synthesis of Natural Products. A list of reviews on General and Synthetic methods is collected at the end of the Report. 

As part of a larger review on synthesis of saturated nitrogen heterocycles, Steele reviewed piperidines, piperidinones, tetrahydroisoquinolines, indolizidines, quinolizidines, and hetero Diels-Alder reactions <94COS95>. 

Synthesis of aromatic heterocycles ch30 Saturated heterocycles ch31 Biological chemistry ch42... 

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