Pd-Catalyzed Regio-, Diastereo-, and Enantioselective [3 + 2] Cycloaddition Reactions: Access to Chiral Cyclopentyl Sulfones

Abstract

The palladium-catalyzed [3 + 2] cycloaddition using in situ generated sulfone-TMM species to construct various chiral cyclopentyl sulfones in a highly regio-, diastereo- (dr >15:1), and enantioselective (up to 99% ee) manner is reported. The present strategy can tolerate different types of sulfone-TMM donors and acceptors, and enables the construction of three chiral centers in a single step, specifically with a chiral center bearing the sulfone moiety. The robust chiral diamidophosphite ligand is the key to the reactivity and selectivities of this transformation.

Recent advances in Pd-catalyzed asymmetric cyclization reactions

“…Soon afterwards, using in situ generated sulfone-TMM species, expedient synthesis of chiral cyclopentyl sulfones 137 bearing three chiral centers via palladium-catalyzed [3+2] cycloaddition was disclosed by Trost and co-workers (Scheme 29). 68 The reaction, which required the presence of a chiral diamidophosphite ligand to facilitate the reactivity and control the selectivity, tolerated a wide range of sulfone-TMM donors and acceptors. 4.1.3.2.3.…”

Pd-Catalyzed Enantioselective (3+2)-Cycloaddition of Vinyl-Substituted Oxyallyl Carbonates with Isocyanates and Ketones

“…However, oxyallyl amphiphiles were seldom exploited in dipolar cycloaddition reactions because the corresponding oxyallyl cation intermediates were only engaged in (4+3) cycloadditions, while the thermodynamic oxyallyl-(3+2) cyclization reactions with 2π acceptors hardly occurred because of the forbidden concerted pathway. Transition-metal-stabilized oxyallyl cations were proved to undergo a variety of annulation reactions including (4+3), (3+2), (5+2) cycloadditions via interceptive allylic substitution mechanism …”