Catalytic Asymmetric [4 + 1] Annulation of Sulfur Ylides with Copper–Allenylidene Intermediates

Abstract

The first copper-catalyzed asymmetric decarboxylative [4 + 1] cycloaddition of propargylic carbamates and sulfur ylides was successfully developed. This strategy led to a series of chiral indolines with synthetically flexible alkyne groups in good yields and with high enantio- and diastereoselectivities (up to 99% yield, 98% ee, and >95:5 dr). A possible mechanism and stereoinduction mode with copper-allenylidenes were proposed as the possible dipolar intermediate.

Transition‐Metal‐Free Decarboxylative Propargylic Substitution/Cyclization with either Azolium Enolates or Acyl Anions

“…[1] Notably,a ll the known catalytic stereoselective variants of this process rely exclusively on transition-metal activation of the propargylic electrophile to deliver allene [2] or alkyne products. [4] Thei ntroduction of orthogonal catalytic activation modes to propargylic substitution will surely open up new opportunities in stereoselective synthesis. In particular, by using ac yclic propargylic carbamate as the substrate,h ighly enantioselective copper-catalyzed formal [4+ +1] and [4+ +2] cycloadditions have been achieved by the groups of Xiao,G ong, and Wu.…”

“…[15] With lessons learnt from these studies and inspired by the reports shown in Scheme 1a, [4] we proposed that effective cycloaddition between (AE)-1a and functionalized aldehydes such as 2acould be realized under cooperative catalysis with NHC and atransition metal (Scheme 2). [15] With lessons learnt from these studies and inspired by the reports shown in Scheme 1a, [4] we proposed that effective cycloaddition between (AE)-1a and functionalized aldehydes such as 2acould be realized under cooperative catalysis with NHC and atransition metal (Scheme 2).…”

Catalytic Asymmetric [3+1]‐Cycloaddition Reaction of Ylides with Electrophilic Metallo‐enolcarbene Intermediates

“…[11a,13] Additionally, recent investigations [14] reported the unique compatibility of copper catalysts in cycloaddition reactions of sulfur ylides. Our inquiry began with the reaction of triisopropylsilyl (TIPS)-substituted enoldiazoacetate 1a with easily accessible and stable α-benzoyl dimethylsulfur ylide 2a at room temperature in the presence of a catalytic amount Cu(CH 3 CN) 4 BF 4 in dichloromethane (DCM).…”

Katalytische Umwandlung von funktionalisierten cyclischen organischen Carbonaten

“…Eine umfassende Übersicht mit unterschiedlichen Arten natürlicher organischer Carbonate sowie ihrer biologischen Herkunft und Eigenschaften wurde kürzlich von Yue und Mitarbeitern verçffentlicht. [12] Dieser Kurzaufsatz wird die neuesten Entwicklungen, Entdeckungen und Mçglichkeiten vorstellen, die sich im Bereich der decarboxylierenden Funktionalisierung von hauptsächlich cyclischen Carbonaten hervorgetan haben und die sich vorwiegend durch die Verwendung der Übergangsmetallkatalyse ergaben. Darüber hinaus ermçglichen die signifikanten Fortschritte bei der Herstellung dieser Heterocyclen einen einfachen Zugang zu synthetisch nützlichen Vinyl-und Alkin-Funktionalisierte cyclische organische Carbonate und deren heterocyclischen Derivate sind eine sehr vielseitige Gruppe heterocyclischer Substrate,d eren katalytische Ringçffnung und Decarboxylierung die Entwicklung neuartiger Synthesewege zur Herstellung stereo-und enantioselektiver C-N-, C-O-, C-C-, C-S-und C-B-Bindungen ermçglicht.…”