Antiselective Three‐Component Mannich Reactions in Thiopyran‐4‐one System

Abstract

The one‐pot, three‐component Mannich reactions of thiopyran‐4‐one 1 with different aromatic aldehydes and aniline derivatives in the presence of catalytic quantities of ZrOCl2.8H2O (15 mol %) led to rapid and high yield formation of various 3‐methylamino substituted derivatives of 1 at room temperature. Spectroscopic and X‐ray analyses of the products suggested the formation of the anti stereoisomers as the major product of the reactions.

rac-3-[(3-Chloroanilino)(4-chlorophenyl)methyl]thian-4-one

“…The title compound is an example of a product from an anti-selective three-component Mannich reaction involving the thiopyran-4-one system (Abaee et al, 2012). The same anti configuration has been found recently in the crystal structures of two other compounds of this series (Abaee et al, 2012;Harms et al, 2012).…”

“…For the preparation and spectroscopic characterization of a series of related compounds and the crystal structure of 3-[(phenylamino)(p-tolyl)methly]dihydro-2H-thiopyran-4(3H)one, see: Abaee et al (2012). For the crystal structures of related compounds, see: Guo et al (2007); Fun et al (2009); Harms et al (2012).…”

rac-3-[(Anilino)(naphthalen-2-yl)methyl]thian-4-one

“…For the preparation and spectroscopic characterization of the title compound and a series of related compounds, see: Abaee et al (2012). For the crystal structure of rac-3-[(3-chloroanilino)(4-chlorophenyl)methyl]thian-4-one, see: Harms et al (2012).…”

A facile four-component Gewald reaction under organocatalyzed aqueous conditions

“…For these entries, reaction times were relatively longer presumably due to lower reactivity of the starting ketone. Because of our interest in developing the chemistry of the thiopyran-4-one system, 32,33 we subjected 1d to the reaction conditions and obtained the expected products as shown in entries 8-10. Based on these results, a mechanism, as depicted in Figure 1, can be suggested for the process.…”