Zn(II)- or Rh(I)-Catalyzed Rearrangement of Silylated [1,1′-Bi(cyclopropan)]-2′-en-1-ols

Carbonylative N-Heterocyclization via Nitrogen-Directed C-C Bond Activation of Nonactivated Cyclopropanes

Under Rh-catalyzed conditions, secondary amines and anilines function as directing groups to facilitate regioselective C–C bond activation of nonactivated cyclopropanes. The resulting amino-stabilized rhodacycles undergo carbonylative C–N bond formation en route to challenging seven- and eight-membered lactams. The processes represent rare examples where C–C bond oxidative addition of nonactivated cyclopropanes is exploited in reaction design.

Gold-catalyzed dual C-C bond cleavage of biphenylenes bearing a pendant alkyne at ambient temperature

We report a catalytic skeletal rearrangement of biphenylenes with a pendant alkyne moiety at room temperature by a cationic gold catalyst, which involves the cleavage of two bonds: the C-C bond of biphenylene and the C(sp)-C(sp2 or sp3) bond. Experimental and theoretical studies revealed that the reaction mechanism included π-activation of the alkyne, ring expansion and 1,2-carbon shift.

Unusual Skeletal Reorganization of Oxetanes for the Synthesis of 1,2-Dihydroquinolines

Skeletal reorganization is a type of fascinating transformations owing to their intriguing mechanisms and utility in complex molecule synthesis. However, only a limited amount of examples are known for most functional groups. Herein, we describe such an unusual process of oxetanes. In the presence of In(OTf)₃ as catalyst, oxetane-tethered anilines reacted unexpectedly to form 1,2-dihydroquinolines. This process not only provides expedient access to dihydroquinolines, but also represents a new reaction of oxetane. Mechanistically, it is believed that the reaction proceeds through initial nitrogen attack rather than arene attack followed by a series of bond cleavage and formation events. Control experiments provided important insights into the mechanism.

Recent Methodologies That Exploit C-C Single-Bond Cleavage of Strained Ring Systems by Transition Metal Complexes

In this review, synthetic and mechanistic aspects of key methodologies that exploit C-C single-bond cleavage of strained ring systems are highlighted. The focus is on transition-metal-catalyzed processes that are triggered by C-C bond activation and β-carbon elimination, with the review concentrating on developments from mid-2009 to mid-2016.

Rhodium(i)-catalysed skeletal reorganisation of benzofused spiro[3.3]heptanes via consecutive carbon–carbon bond cleavage

Benzofused spiro[3.3]heptane derivatives undergo skeletal reorganisations involving two consecutive carbon–carbon bond cleavages in the presence of rhodium(i) catalysts to afford substituted naphthalenes.