Sulfoxide-Directed Intramolecular [4 + 2] Cycloadditions between 2-Sulfinyl Butadienes and Unactivated Alkynes

Abstract

Sulfinyl dienynes undergo thermal and catalyzed IMDA cycloadditions, often at room temperature, to produce cyclohexa-1,4-dienes with good yields and high selectivities. Additionally, the products preserve a synthetically useful vinyl sulfoxide functionality. The selective manipulation of the double bonds in the cycloadducts has also been examined in this work.

Sulfoxide-Directed Enantioselective Synthesis of Functionalized Tetrahydropyridines

“…Previously, we have reported the stereocontrolled cyclization of hydroxy sulfinyl dienes to afford enantiopure 3-sulfinyl dihydropyrans . Building upon these precedents and our interest in developing new building blocks via novel sulfoxide-based synthetic transformations, especially those that allow for multiple chirality-transfer operations, we envisaged that the related aminodienes 1 might behave similarly and undergo an intramolecular conjugate addition to provide a diverse range of stereodefined allylic sulfinyl 1,2,3,6-tetrahydropyridines 2 . We detail herein our preliminary studies aimed at this goal, as well as the [2,3]-sigmatropic rearrangement of a range of these unexplored allylic sulfoxides 2 to afford functionalized tetrahydropyridin-3-ols 3 (Scheme ) …”

Sulfinyl-Mediated Stereoselective Overman Rearrangements and Diels–Alder Cycloadditions

“…The diastereoselectivity of Diels–Alder cycloadditions of acyclic chiral dienes with a nitrogen substituent at the allylic position has been studied, and while the results are dependent on the diene structure and the nature of the dienophile, it was established that for maleic anhydride, an endo approach syn to the protected nitrogen functionality on a conformer that eclipses the allylic hydrogen and the diene was operative . On the other hand, our group has a long-standing interest in the development of the Diels–Alder chemistry of 2-sulfinyl butadienes to produce adducts that preserve the useful vinyl sulfoxide moiety and often with high diastereoselectivities that even override the powerful directing effect of an allylic oxygen substituent. , Typically, for S S sulfinyl dienes as drawn in this paper, simple Z or unsubstituted 2-sulfinyl dienes undergo highly selective Diels–Alder processes with maleimides and maleic anhydride with an endo approach to the bottom face of the diene moiety (α-endo), as shown by X-ray crystallography , or chemical correlations . In this context, we were intrigued about the viability and, particularly, the selectivity of the cycloadditions of our amido sulfinyl dienes, especially for diastereomers (±)- 23 , with opposing elements of stereocontrol.…”

Base-Induced Sulfoxide-Sulfenate Rearrangement of 2-Sulfinyl Dienes for the Regio- and Stereoselective Synthesis of Enantioenriched Dienyl Diols

“…6, 142.4, 142.0, 130.6 (2C), 125.4 (2C), 114.6, 43.5, 33.1, 32.8, 26.2, 25.91, 25.87, 21.4 General Procedure for the Synthesis of Sulfinyl Dienes, 1. Dienes (E,Z)-1a, 18 (E,E)-1b, 21 (E,Z)-1h, 18 and (E,Z)-1k 9 were already reported.…”