Francesca Sotgiu

Metalation reactions. XIV. Regiospecific preparation of polysubstituted benzenes via mono- or di-lithiation reactions of aromatic thioethers☆

Abstract The preparation of polyfunctionalized aromatic thioethers either by one-step dilithiation or by two successive one-flask monometalation reactions is described. By acting on 1 two equal or different electrophiles one on the thiomethyl group and one in the ortho -position with respect to it are introduced; by acting on 11 and on 35 the substitution involves the thiomethyl carbon atom and that in the ortho -position with respect to the alkoxy group. In the case of the homologous isopropylthio (23) the substitution involves the two aryl carbon atoms in the ortho -position to both functions. In the case of the p -disubstituted isomers (49, 59) analogous behaviour to ortho isomers in one-step metalation reaction is observed, while the two hydrogen atoms in the ortho -positions to the methoxy group are substituted when two successive monometalations are employed. The metalation of 40 results low selective. The behaviour of 79 and 93 is analogous to 1, while 72, 88 and 96 undergo only one-step monometalation reactions.

Metallation reactions. XXVI. α,α′-Dimetallation of 1,2-bis(methylthiobenzene)

Abstract α,α′-Dimetallation of bis(methylthio)benzene (1) with butyllithium or with superbases gives 2 with good yield. This species allows the simultaneous introduction of two electrophiles in thiomethyl groups. Alternatively it was possible to functionalize these groups with two different electrophiles by two successive one-flask monometallations. Compound 2 rise to gives heterocyclic compounds.

HETEROCYCLIC COMPOUNDS STUDIES, SYNTHESIS OF 1,5-BENZOXATHIEPINES

Abstract 1,5-Benzoxathiepinic derivatives have been obtained in good yields by the reaction of epichlorohydrines with 2-hydroxybenzenethiols in an aqueous alkalinic hydroxides medium. Their structures have been determined by 13C NMR spectroscopy.

CLEAVAGE OF THE ETHEREAL BOND. XI. THE REACTION OF ALLYLIC ORGANOMAGNESIUM HALIDES WITH 1,3-BENZOXATHIOLE AND 1,3-BENZODIOXOLE

Die Al1yl-Grignard-Verbindungen (II) reagieren in Toluol mit Benzoxathiol (Ia) bzw. Benzodioxol (Ib) unter Spaltung der Atherbindung und anschliesender Allylumlagerung zu den Alkenylthiobzw.