The Behavior of Thiochromanone and Isothiochromanone Sulfoxides in the Schmidt Reaction: Isolation of a Novel Azide Product from Thiochromone Sulfone

Abstract

. Can. J . Chem. 53,276(1975).The Schmidt reaction has been carried out on thiochroman-4-one 1-oxide and a number of related sulfoxides. In all cases lactam formation by attack of HN3 on the carbonyl group of the keto sulfoxide appears to predominate, with no evidence for sulfoximine formation. The question of aryl vs. alkyl migration, as in other systems, is dependent on the degree of substitution of the alkyl group. When the Schmidt reaction was carried out upon thiochromone 1,l-dioxide two products, the lactam resulting from preferential vinyl migration and a novel a-azido sulfone resulting from 1,4-addition, were obtained. On a effectue la reaction de Schmidt sur la thiochromanone-4 oxyde-1 et un certainnombre de sulfoxydes qui lui sont apparent&. Dans tous les cas, il y a formation de lactame par attaque de HN3 sur le groupement carbonyle du cCto-sulfoxyde et cette riaction semble predominante; on n'a trouve aucune preuve expirimentale pour la formation d'une sulfoxymine. La question de la migration des groupes aryles par opposition a la migration a des groupes alkyles depend d u degre de substitution en accord avec ce qui a CtC observe dans d'autres systkmes. Lorsque I'on effectue la rtaction de Schmidt sur la thiochromonedioxyde-1

Chemo- and Diastereoselectivity in the Dimethyldioxirane Oxidation of 2,3-Dihydro-4H-1-benzothiopyran-4-ones and 4H-1-Benzothiopyran-4-ones. Unusual Reactivity of 4H-1-Benzothiopyran-4-one 1-Oxides1

“…A similar chemoselectivity has been observed in the DMD oxidation of 2,3-dihydro-1,5-benzothiazepin-4(5 H )-ones 13h. Earlier oxidations of the parent 1-thiochroman-4-one ( 1a ) and its 2- or 3-methyl-substituted derivatives to their sulfoxides have been performed by using ice-cold H 2 O 2 /acetic acid, , sodium periodate, or m -CPBA, whereas the enantioselective sulfoxidation of the thiochromanone 1a was accomplished by H 2 O 2 in the presence of chloroperoxidase (CPO) 20 or iodosylbenzene and chiral, nonracemic porphyrin catalyst . Very recently two mild and efficient procedures have been published for the oxidation of sulfides including 1-thiochromanone ( 1a ) to their sulfoxides, one of them utilizes H 2 O 2 in the presence of titanium derivatives supported on silica, whereas ceric ammonium nitrate (CAN) and hydrated silica gel were used in the other case …”

“…A point of interest was the diastereoselectivity in the sulfoxidation of 2-substituted 1-thiochroman-4-ones 2a − c and 3a by DMD. Although some sporadic mention has been made on the formation of diastereomers in the literature, 19c,− neither their separation nor the determination of the relative configuration has been carried out. We succeeded in separating the mixtures of the cis and trans diastereomers of 2a and 2b by column chromatography, which allowed the unequivocal assignment of the NMR signals to the each diastereomer.…”

Photochemical rearrangements of substituted thiochromanone sulfoxides

“…The synthesis of 3,3-dimethylisothiochromanone has also been described earlier (25). Two representative procedures (Methods A , B) are described below.…”

Schmidt Reaction of E‐3‐Benzylidenechromanones and E‐3‐Benzylidenethiochromanones

“…Moreover, there are important variants of this reaction, developed mainly by Aubé et al [2,3], which include rearrangements through interactions of carbocations and alkyl azides or carbonyl compounds and alkyl azides, either intermolecularly or intramolecularly. Schmidt reaction of chromanones and their analogues has been studied by a number of groups [4][5][6][7][8][9][10][11][12][13]. Schmidt reaction of E-3-benzylideneflavanones (1) (Figure 1), done by us, produced some novel results [14][15][16].…”