Palladium-Catalyzed ortho-C–H Glycosylation/ipso-Alkenylation of Aryl Iodides

Abstract

This report describes the first example of palladium-catalyzed ortho-C–H glycosylation/ipso-alkenylation of aryl iodides, and the easily accessible glycosyl chlorides are used as a glycosylation reagent. The reaction is compatible with the functional groups of the substrates, and a series of C-aryl glycosides have been synthesized in good to excellent yield and with excellent diastereoselectivity. It is found that a cheap 5-norbornene-2-carbonitrile as a transient mediator can effectively promote this reaction. In addition, ipso-arylation and cyanation were also realized by the strategy.

Catellani Reaction: An Enabling Technology for Vicinal Functionalization of Aryl Halides by Palladium(0)/Norbornene Cooperative Catalysis

“…[48] Very recently, the Cheng and Liang groups have independently achieved the C-H glycosylation reaction of aryl iodides by utilizing different glycosyl chlorides as the alkylation reagents. [49][50] Gratifyingly, azirines, epoxides and aziridines could also be used as alternative alkylating agents to promote the ortho alkylation of aryl halides (Schemes 18-20). In 2010, Lautens described an interesting Pd/NBE-catalyzed domino reaction to furnish indoles 34 by using 2H-azirines as bifunctional agents (Scheme 18).…”

“…[ 48 ] Very recently, the Cheng and Liang groups have independently achieved the C—H glycosylation reaction of aryl iodides by utilizing different glycosyl chlorides as the alkylation reagents. [ 49‐50 ]…”

Pd‐Catalyzed Ortho‐Directed C—H Glycosylation of Arenes Using N‐linked Bidentate Auxiliaries

“…[6][7] The ortho C-H bonds of arylcarboxamide or 2-arylacetamide substrates equipped with amide-linked N,N-bidentate auxiliary 8-aminoquinoline (AQ or Q) can be activated to form 5 or 6-membered palladacycle intermediates, which then react with glycosyl chloride donors via oxidative addition and reductive elimination to give the corresponding C-glycosides in good to excellent yield and with excellent diastereoselectivity. [8][9][10][11][12][13][14] Phenol type substrates can undergo similar ortho C-H glycosylation using a carbamate-linked AQ auxiliary. Herein, we report an extension of this Pd-catalyzed ortho-directed Scheme 1 Synthesis of C-aryl-glycosides via Pd-catalyzed ortho-directed C-H glycosylation with glycosyl chlorides C-H glycosylation reaction strategy to arylamine, benzylamine and N-heteroarene substrates using various urea-linked or amide-linked bidentate auxiliaries.…”

Non-innocent hybrid cycloolefin ligands for palladium/olefin cooperative catalysis

“…While in most cases this co-catalyst should be used in sub-or even super-stoichiometric amounts to ensure reactivity, this process has been regarded as an efficient protocol for vicinal difunctionalization of arene substrates. However, the Pd/NBE cooperative catalysis is constrained to NBE and its structurally modified derivatives in which the bicyclo[2.2.1]heptene skeleton remains [22][23][24][25][26][27][28] , and to date people have to admit that the NBE structure is indispensable due to its unique structural feature 17 . It has been a long-standing question that whether or not an unstrained olefin without the NBE skeleton could be used in the covalent cooperative catalysis 29 .…”