39141-54-3Relevant articles and documents
Reactions of δ-valerolactone with lithio trithio-orthoformates
Yates, Peter,Seif-El-Nasr, Azza,Stanton, Jennifer,Krepinsky, Jiri J.
, p. 415 - 422 (2007/10/02)
δ-valerolactone (3), on treatment with tris(methylthio)methyllithium (7) followed by weakly acidic aqueous work-up, gave a tautomeric mixture of 1,1-bis(methylthio)-6-hydroxy-2-hexanone (8a) and tetrahydro-2-bis(methylthio)methyl-2-pyranol (8b).Under analogous conditions 3 reacted with tris(phenylthio)methyllithium (10) to form tetrahydro-3-(phenylthiocarbonyl)-2-pyranone (11).With 2-(methylthio)-1,3-dithian-2-yllithium (16) it gave a tautomeric mixture of 2-(5-hydroxy-1-oxopentyl)-2-(methylthio)-1,3-dithiane (17a) and 2-(tetrahydro-2-hydroxy-2-pyranyl)-2-(methylthio)-1,3-dithiane (17b).Treatment of 17 with methanol in the presence of acidic ion-exchange resin gave a mixture of 2-(5,6-dihydro-3-(methylthio)-2(4H)-pyranyl-1,3-dithiane (20), 2-(tetrahydro-2-methoxy-2-pyranyl)-1,3-dithiane (21), and 2-(tetrahydro-2-methoxy-(4-methylthio)-2-pyranyl)-1,3-dithiane (22).Similar treatment of 20 gave a mixture of 20, 21, and 22.Compound 21 was synthesized independently by similar treatment of 2-(tetrahydro-2-hydroxy-2-pyranyl)-1,3-dithiane (23).The origins of the anomalous products are discussed briefly.It is concluded that because of these anomalies the preparation of tetrahydro-2-hydroxypyran-2-carboxylic acid acetals and related glycosides via trithio-orthoformate derivatives can encounter difficulties, although dithioacetales may serve this purpose. Key words: 1,3-dithianes, α-hydroxy acids, δ-lactones, trithio-orthoformates.
