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A gold-catalyzed cascade cyclization of O-tethered 1,7-enynes bearing a cyclopropane moiety has been reported in this communication, affording multi-substituted furans in moderate to good yields. The reaction proceeded through an intramolecular O-nucleophilic addition and 3,3-sigmatropic rearrangement followed by ring-opening of the cyclopropane unit along with the further reaction with electrophiles. The C–C bond cleavage of a strained cyclopropane moiety in the presence of a gold catalyst and the aromatization provided the driving force for this cascade cyclization. The practical transformations of the obtained diiodinated furan have also been indicated. [ABSTRACT FROM AUTHOR]

A novel gold(i)-catalyzed intramolecular tandem cyclization reaction of ortho-(arylethynyl)arenemethylenecyclopropanes provided an efficient approach to prepare functionalized 11H-benzo[a]fluorene derivatives in moderate to good yields. Further transformations as well as applications of the products have been presented and a plausible reaction mechanism has also been proposed on the basis of deuterium labeling and control experiments. [ABSTRACT FROM AUTHOR]

We have investigated the ligand effect on the gold-activated intramolecular amidiniumation of formamidine having a terminal alkyne, and observed the transformation of vinyl gold species into a gem-digold intermediate comprising two C–Au σ bonds, which represents a new binding mode for gem-digold species in the gold-promoted transformation of alkynes. [ABSTRACT FROM AUTHOR]

An effective synthetic protocol for structurally diverse 4-acyloxy-1,2-dihydroquinoline compounds has been accomplished by a gold(i)-catalyzed tandem [3,3]-rearrangement and intramolecular hydroamination of propargylic esters, affording the desired products in good yields. Moreover, the asymmetric variant of this cyclization has also been achieved using a chiral nitrogen acyclic carbene (NAC) gold(i) complex. These products have application in the enantioselective synthesis of an aromatase inhibitor within three simple steps. [ABSTRACT FROM AUTHOR]

A convenient and efficient synthetic method has been developed to construct highly functionalized polycyclic indoline skeletons with four contiguous stereocenters, which are of great importance in biological and pharmaceutical chemistry. The selective formation of either the oxabridged-ring or ring-opening polycyclic indoline derivatives can be controlled by using different gold catalytic systems. A variety of polycyclic indoline derivatives were obtained in moderate to good yields under mild conditions with moderate to excellent enantioselectivity. [ABSTRACT FROM AUTHOR]

The synthesis of medium-sized heterocycles possessing a trans double bond is still a challenge. Herein, gold(i)-catalyzed 1,2-acyloxy migration/intramolecular cyclopropanation/ring enlargement cascade reaction of furans has been developed, providing highly efficient access to ten- and eleven-membered heterocycles with a broad substrate scope under mild reaction conditions. The reaction outcome features high chemoselectivity at the C5-position of furan. Moreover, a trans-double bond was embodied in the medium ring system. [ABSTRACT FROM AUTHOR]