A novel visible-light-induced cascade reaction for the preparation of ester-functionalized polyheterocycles was developed under metal-free conditions, which was initiated by an intermolecular radical addition to a carbon-carbon double bond of N-arylacrylamide derivatives using alkyl carbazate as the ester source followed by cyano-mediated cyclization. The desired phenanthridine derivative products were isolated in moderate to high yields with broad substrate scope.
A formal 1,6-conjugated addition-mediated [2+1] annulation to synthesize spiro[2.5]octa-4,7-dien-6-one with p-quinone methides and sulfur ylides has been described. This domino-type process was highly diastereoselective and exhibited good functional group tolerance and scalability without the use of metals and bases.
An efficient one-pot approach for the synthesis of spiro[2.5]octa-4,7-dien-6-ones by employing para-quinone methides has been developed. The reaction proceeded smoothly in high yields under mild conditions without the use of metals. Moreover, all products obtained herein contained two or three consecutive quaternary centers.
A palladium-catalyzed remote 1,n-arylamination (from 1,3-to 1,11-arylamination) of unactivated terminal alkenes with aryl iodides and arylamines has been realized. This three-component reaction proceeded via Pd-catalyzed Heck arylation, alkene isomerization, and aza-Michael addition, exhibiting good regio-and chemoselectivity, and wide substrate scope. Preliminary mechanistic studies indicated that the in situ generated ortho/para-quinone methide intermediates served as the driving force for the alkene isomerization and promoted the rearomatization upon nucleophilic amination.
An
unprecedented acid- and ligand-controlled divergent allylation
of indoles with unactivated skipped enynes via Pd hydride catalysis
has been disclosed. This redox-neutral transformation went through
multiple hydropalladation insertion, β-hydrogen elimination,
π–σ–π isomerization, and allylic substitution
steps. This method not only provides a platform for synthesizing indolenines
and N-allylindoles but also allows facile access
to functional 1,3-dienes with high atom and step economy.
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