Synthesis and Diels-Alder reactivity of sulfinyl homo- and heterodienes obtained via enantiopure sulfenic acids

Abstract

This account is intended to provide a brief survey on our contribution in the field of enantiopure sulfinyl homo and hetero dienes which we are able to obtain via enantiopure sulfenic acids. The chemistry of these sulfinyl-dienes was mainly developed taking into account the practical importance of stereoselective homo and hetero Diels-Alder cycloadditions, able to supply useful intermediates in the synthesis of target molecules.

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.…”

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

“…In contrast, tetrasubstituted dienyne 2f gave a 66:34 mixture of 3f and 4f . The reduced diastereoselectivity observed may be due to conformational changes around the carbon−sulfur bond in order to minimize A 1,2 allylic strain on the diene moiety . As alkynyl bromides are known to be effective substrates in thermal cycloadditions of similar dienynes not bearing the sulfinyl moiety, we decided to study the IMDA of dienyne 2k .…”