The efficient Pd-catalyzed Heck reaction of diverse tertiary alkyl halides with alkenes has been developed. Unactivated tertiary alkyl halides efficiently react at room temperature under visible light irradiation with no exogenous photosensitizers required. For activated tertiary alkyl halides, the same catalytic system works well without light. These methods offer a general access to electronically diverse alkenes possessing quaternary and functionalized tertiary allylic carbon centers. The substituents at these centers include alkyl-, carbalkoxy-, tosyl-, phosphonyl-, and boronate groups. It was also shown that the end-game mechanism of this transformation may vary depending on the type of the substrates used.

Activation of inert molecules like CO2 is often mediated by cooperative chemistry between two reactive sites within a catalytic assembly, the most common form of which is Lewis acid/base bifunctionality observed in both natural metalloenzymes and synthetic systems. Here, we disclose a heterobinuclear complex with an Al–Fe bond that instead activates CO2 and other substrates through cooperative behavior of two radical intermediates. The complex Ldipp(Me)­AlFp (2, Ldipp = HC­{(CMe)­(2,6- i Pr2C6H3N)}2, Fp = FeCp­(CO)2, Cp = η5-C5H5) was found to insert CO2 and cyclohexene oxide, producing LdippAl­(Me)­(μ:κ2-O2C)­Fp (3) and LdippAl­(Me)­(μ-OC6H10)­Fp (4), respectively. Detailed mechanistic studies indicate unusual pathways in which (i) the Al–Fe bond dissociates homolytically to generate formally AlII and FeI metalloradicals, then (ii) the metalloradicals add to substrate in a pairwise fashion initiated by O-coordination to Al. The accessibility of this unusual mechanism is aided, in part, by the redox noninnocent nature of Ldipp that stabilizes the formally AlII intermediates, instead giving them predominantly AlIII-like physical character. The redox noninnocent nature of the radical intermediates was elucidated through direct observation of LdippAl­(Me)­(OCPh2) (22), a metalloradical species generated by addition of benzophenone to 2. Complex 22 was characterized by X-band EPR, Q-band EPR, and ENDOR spectroscopies as well as computational modeling. The “radical pair” pathway represents an unprecedented mechanism for CO2 activation.

Computational prediction of the oxidative ability of hypervalent iodine reagents was performed based on redox potentials, calculated at the B3LYP/6-311+G(d,p) level of theory with the SDD ECP46MDF pseudopotential for the iodine atom.

A cobalt-catalyzed method for the hydrogermylation of alkynes is reported, providing a selective and accessible route to (E)-β-vinyl(trialkyl)germanes from terminal alkynes and HGeBu 3 . As shown in multiple examples, the developed method demonstrates a broad functional group tolerance an practical utility for late-stage hydrogermylation of natural products. The method is compatible with alkynes bearing both aryl and alkyl substituents, providing unrivaled selectivity for previously challenging 1°alkyl-substituted alkynes. Moreover, the catalyst used in this method, Co 2 (CO) 8 , is a cheap and commercially available reagent. Conducted mechanistic studies supported the syn-addition of Bu 3 GeH to an alkyne π-complex.

Novel regioselective approach to the synthesis of (1H-1,2,3-triazol-1-yl)furoxans based on Lewis acid-catalyzed Wolff cyclocondensation of aminofuroxans with diazo-β-dicarbonyl compounds has been developed. This approach allows to involve aminofuroxans as substrates which are very weak nucleophiles and usually do not participate in reactions with common electrophiles.

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Metal-mediated aryl fluoride activation not only presents challenges because of the thermodynamically robust C–F bond but also provides opportunities to develop C–C coupling reactions with this unconventional electrophile. Here, we report that the metallanucleophile, K[CpFe(CO)2] (KFp), is readily arylated by aryl fluorides to provide CpFe(CO)2Ar (FpAr) complexes under ambient conditions in the absence of any catalyst, contrary to previous literature reports. This C–F activation likely proceeds by a SNAr mechanism rather than the more common oxidative addition pathway for metal-mediated C–F cleavage. Facile access to FpAr derivatives has enabled further development of Fe-promoted coupling reactions of aryl fluorides with alkenes and alkynes. Under stoichiometric Fe conditions, Heck-type coupling reactions with aryl fluoride electrophiles are reported herein. Various aryl fluorides were found to couple with olefins to provide E-alkene products; aliphatic derivatives unexpectedly underwent reduction to 1,2-disubstituted ethane products to varying extents. Aryl fluorides were also found to couple with 5-decyne to yield indene derivatives in a one-pot manner; indenone and indanone products were also observed in selected cases. A mechanistic investigation to identify the apparently potent hydride donor generated under these conditions was conducted, leading to a mechanistic hypothesis involving the intermediacy of metal carbonyl-capped, triple-decker ferrocene compounds as reductants. Despite the involvement of these di-iron intermediates limiting stoichiometric product yields, the observed C–C coupling reactions expand the limits of organofluorine chemistry.

<a></a><a>We demonstrated unprecedentedly that Co complexes can catalyze hydrogermylation of alkynes. Subsequently, a selective, accessible method was developed to synthesize E-(β)-vinyl(trialkyl)germanes from various terminal alkynes with high yields. As shown on multiple examples, the developed method demonstrates broad functional group tolerance and practical utility for late-stage hydrogermylation of drugs and natural products. The method is compatible with alkynes bearing both aryl and alkyl substituents, providing unrivaled selectivity for previously challenging 1° alkyl-substituted alkynes. Moreover, the catalyst used in this method, Co₂(CO)₈, is a cheap and commercially available reagent. Conducted mechanistic studies supported syn-addition of Bu₃GeH to an alkyne</a> π-complex.