Ketones ethylene derivatives, synthesi

Reaction of boranes with diazo compounds Synthesis of ketones from ethylene derivatives... 

A soln. of the startg. m. and 4 equivalents ketal heated ca. 8 hrs. at 100° in toluene containing 2,4-dinitrophenol as catalyst, and the intermediate ketone treated at 0° with NaBH4 in methanol > product. Y up to 81% purity 98%. -This olefinic ketal Claisen reaction is useful for preparing trans-disubst as well as trans-trisubst. olefinic bonds. The above producure is the last of a succession of 3 similar steps. F. e. and catalysts s. W. S. Johnson et al., Am. Soc. 92, 4463 (1970) Proc. Natl. Acad. Sci. U.S. 67, 1462, 1465, 1810, 1824 (1970) geospecific synthesis of ethylene derivs., review, s. J. Reucroft and P. G. Sammes, Quart. Rev. 25,135 (1971). 

Synthesis of ketones from aldehydes from ethylene derivs. 

Phosphoric acid acetic acid Synthesis of cyclic ethylene derivs. from cyclic ketones... 

Synthesis ofLysergic Acid, By reacting N-benzoyl-3-(B-carboxyethyl)-dihydroindole (see JCS, 3158 (1931) for the preparation of this compound) with thionyl chloride, followed by aluminum chloride gives l-benzoyl-5-keto-l,2,2a,3,4,5-hexahydrobenzindole. This is then brominated to give the 4-bromo-derivative, which is converted to the ketol-ketone by reacting with methylamine acetone ethylene ketol. This is then hydrolized by acid to yield the diketone and treated with sodium methoxide to convert it to the tetracyclic ketone. Acetylate and reduce this ketone with sodium borohydride to get the alcohol, which is converted to the hydrochloride form, as usual. 

The transformation of tetrasubstituted ethylenes into 1,2,4-trioxolanes may also be achieved if the ozonolysis is carried out in the presence of a foreign carbonyl compound as described in Section 4.33.3.4. With formaldehyde as added carbonyl compound, 3,3-disubstituted derivatives are obtained, whereas in the presence of excess ketone (e.g. by using the latter as solvent), the ozonolysis gives rise to tetrasubstituted 1,2,4-trioxolanes which are difficult to prepare by other methods. Reactions (163) -> (164) and (165) -> (166) provide two examples of this versatile 1,2,4-trioxolane synthesis. Unlike the parent system (2), alkyl- and/or aryl-substituted 1,2,4-trioxolanes generally are stable, non-explosive compounds. Mixtures of crossed ozonides (cf. Section 4.33.3.1.1) or of cis and trans isomers can be separated by thin layer, column or gas chromatography. The cis isomers of symmetrical 3,5-disubstituted 1,2,4-trioxolanes are meso forms, whereas the corresponding trans isomers represent racemates which in some cases have been resolved into their optical... 

This sequence transforms acyclic ketones and aldehydes into a-methylene ketones and a-methyl-a,)5-unsaturated ketones and aldehydes It has been illustrated by the synthesis of eucarvone, ( )-nuciferal and ( )-manicone This ring-opening of chlorosiloxycyc-lopropanes with ClSiMea elimination appears to be a practical route to Z or a,)5-ethylenic aldehydes and ketones depending on the stereochemistry of the reactants. For example, conversion in MeOH-NEta at 20°C of the 2-chloro-2-methyl-3-pentyl-l-trimethylsiloxycyclopropanes (derived from the addition of the chloromethylcarbene to the E and Z silyl enol ethers of n-heptanal) leads either to or Z 2-methyl-oct-2-enal (equation 65). ... 

In a paper published along with that of Stevens and Wentland20 and in agreement with these authors, Keely and Tahk23 reported the independent synthesis of dl-mesembrine, also from I-methyl-3-(3,4-dimethoxyphenyl)-2-pyrroline and methyl vinyl ketone. In their work the cyclopropyl derivative 3b was prepared from the reaction of the anion of 3,4-dimethoxyphenylacetonitrile (lc) with ethylene dibromide in dimethyl sulfoxide and its sodium salt as solvent and base. Reduction with ethereal diisobutylaluminum hydride gave the aldehyde, which was condensed with excess methylamine in benzene-ether solution with calcium oxide as the dehydrating agent. 

A short synthesis of the tetracyclic y-lycorane derivatives (13a) and (13b) from isocarbostyrils has been reported (Scheme 2). N-Alkylation of (11a) and (11b) with 5-bromo-2-pentanone ethylene ketal gave the ketals (12a) and (12b), respectively. Acid hydrolysis provided the corresponding ketones which upon base-catalysed cyclization yielded compounds (13a) and (13b), respectively. 

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