Synthesis of olefins

Using one of our methods of analysing the synthesis of olefins, that is FGl to an alcohol, write down both the alcohols from which you might make TM 88 and see which you prefer. 

Formation of Functional Groups. Metal carbonyls have been used in a number of cases to synthesize organic molecules containing particular functional groups (147—149). A synthesis of olefins from -dihahdes has been reported (148) ... 

Synthesis of olefins by stereospecific rerbctfve elimination of S-hydroxyaikyl selenides (a variant at Peterson olefinatlon) by means of MeSOjCI. HCIO4 or P2I4. 

Crude oil processing is mainly aimed towards the production of fuels, so only a small fraction of the products is used for the synthesis of olefins and aromatics. In Chapter 3, the different crude oil processes are reviewed with special emphasis on those conversion techniques employed for the dual purpose of obtaining fuels as well as olefmic and aromatic base stocks. Included also in this chapter, are the steam cracking processes geared specially for producing olefins and diolefms. 

Allylic sulfones and a, /5-unsaturated sulfones are known to be in equilibrium314-319. Allylic sulfones, such as 242, isomerize to a, /5-unsaturated sulfones 243 upon treatment with a catalytic amount of potassium t-butoxide in dry THF. The a, /5-unsaturated sulfones can be converted to the corresponding olefins upon desulfonation with sodium amalgam320 or aluminium amalgam294,321. Since treatment of allylic sulfones with potassium-graphite gives 2-alkenes, alkylation of allylic sulfones and subsequent desulfonation is a useful process for the synthesis of olefins, as shown in Scheme 6. 

Two examples of this method for the synthesis of olefins deuteriated exclusively at the vinyl position by the simple use of deuteriated solvents are shown in equations 64198 and 65199. Due to the alkaline reaction conditions no subsequent isomerization of the initially produced alkene is observed. 

VI. MISCELLANEOUS SYNTHETIC USES OF SULFONES A. Synthesis of Olefins... 

Recent trend in the synthesis of olefinic pheromones is the use of transition metal-catalyzed cross coupling reaction for carbon-carbon bond formation. Scheme 8 summarizes a synthesis of the termite trail marker pheromone, (3Z,6Z)-3,6-dodecadien- l-ol (2) by Oehlschlager [19]. The key-step is the palladium-catalyzed cross-coupling of allylic chloride A and alkenylalane B. 

The method is of general applicability7 for the synthesis of olefins. Other sulfonyl chlorides, RCH2SO2CI, have been used where R = H, C2H5, CeHs, and C6H5CH2 other diazoalkanes that have been used are diazoethane and l-diazo-2-methyl-propane. In all cases the olefins form without double-bond migration. 

Watt and Drummond, were considered to be inert for C-C bond forming reactions. However, by the expedient of transmetallation to Cu, Ni, Zn, Li, and Al, methodologies for the stereoselective synthesis of olefins and dienes, as well as unusual heterocycles, aromatics and their ring-annulated products are now available which are beginning to make impact on material science, e. g. synthesis of pentacenes and polyphenylenes. Takahashi and Li provide evidence that, with further developments in transmetallation and handling the zirconacycles outside of the Schlenk tube techniques, synthetic utility will increase and new catalytic reactions will be developed. 

Recently organosilicon compounds are being used for the synthesis of olefines by elimination reactions both in acidic and basic conditions. Thus P hydroxysilanes give defines. These reactions have been shown to be highly stereospecific. The acid catalysed elimination taking place by an anti pathway and the base induced elimination taking place by a syn pathway. 

Another synthesis of olefins has been described in which the desulphurization of thiirans by triphenylphosphine is featured.72 There have been many reports of the synthesis of compounds of the type (63). These form charge-transfer complexes with acceptors such as tetracyanoquinodimethane which have metallic properties. The... 

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