Lewis Base Catalyzed Selenofunctionalization of Alkynes with Acid-Controlled Divergent Chemoselectivity

Lewis base catalyzed and Brønsted acid controlled chemodivergent electrophilic selenofunctionalizations of alkynes were developed for the first time.Various selenium-containing tetrasubstituted alkenes were readily obtained in moderate to excellent yields with complete E/Z selectivities.As the substrates were 1-ethynyl naphthol derivatives,linear selenium-containing tetrasubstituted alkenes were produced via intermolecular oxygen nucleophilic attack in the absence of acid additive;in contrast,cyclic selenium-containing tetrasubstituted alkenes were generated through intramolecular carbon nucleophilic capture with the addition of Brønsted acid.

Unusual Single Electron Transfer Reactions between Alkenes and Iodine Electrophiles

The electrophilic addition to an alkene with an electrophile has been widely studied and applied in organic synthesis.The organic chemistry textbook describes the classical reaction between an alkene and an iodine electrophile(such as elemental iodine and N-iodosuccinimide(NIS))as a typical ionic reaction,in which an iodonium ion is formed and then attacked by a nucleophile.However,in this article,we report a new and unusual reaction mode between an alkene and NIS;that is,a single electron transfer(SET)process occurs between these two reactants by forming an electron-donor acceptor complex.Not only does this unusual single electron transfer reaction between an alkene and NIS add fundamentally important knowledge to organic chemistry,it also provides a valuable synthetic method as the new SET reaction mode with opposite regioselectivity as compared with the traditional ionic mode.

State-of-the-Art in Electrophilic Trifluoromethylthiolation Reagents

The trifluoromethylthio group （SCF3） is a fluorine chemotype that has experienced a strong acceleration of in- terest in the recent years. It is particularly true of the construction of new fluorinated architectures by electrophilic trifluoromethylthiolation. The spread of knowledge was already very active in this research domain in the sixties; however, gaseous and highly toxic trifluoromethanesulfenyl chloride （CF3SC1） was the only reagent available at that time. Nowadays, one really can speak of a revival in the field thanks to the rapid development of a wide pano- ply of reagents that are stable and easy to handle. This review provides a historical perspective of the development of shelf-stable electrophilic trifluoromethylthiolation reagents.

Controlled semi-Pinacol rearrangement on a strained ring:Efficient access to multi-substituted cyclopropanes by group migration strategy

We describe a versatile electrophile addition/SPR sequence of readily available cyclopropyl carbinols that affords multi-substituted carbonylated cyclopropanes with high stereo-fidelity.This approach tolerates various heteroatom electrophiles,migration of carbon moiety of all possible hybridization states,facile ring reorganization and natural compound valorization.The examples represent an unprecedented version of SPR wherein migration to a non-benzylic bulky tertiary carbo-cation is realized with promising enantiocontrol.

TEMPO-Regulated Regio-and Stereoselective Cross-Dihalogenation with Dual Electrophilic X^(+) Reagents

A TEMPO catalyzed cross-dihalogenation reaction was established via redox-regulation of the otherwise complex system of dual electrophilic X+reagents.Formally,the ICl,BrCl,I_(2) and Br_(2) were generated in-situ,which enabled high regio-or stereoselective access to a myriad of iodochlorination,bromochlorination and homo-dihalogenation products with a wide spectrum of functionalities.With its mild conditions and operational simplicity,this method could enable wide applications in organic synthesis,which was exemplified by divergent synthesis of two pharmaceuticals.Detailed mechanistic investigations via radical clock reaction,pinacol ring expansion and Hammett experiments were conducted,which confirmed the intermediacy of halonium ion.In addition,a dynamic catalytic model based on the versatile catalytic role of TEMPO was proposed to explain the selective outcomes.

Synthesis of 3-Methylthioindoles via Intramolecular Cyclization of 2-Alkynylanilines Mediated by DMSO/DA/lSO-d_(6) and SOCI_(2)

The intramolecular cyclization of 2-alkynylanilines mediated by DMSO/SOCI_(2) was found to afford biologically interesting 3-methylthioindoles,which are rarely obtained by the exiting methods.DMSO could also be replaced with its deuterated counterpart,enabling the method applicable to the construction of indole skeleton bearing a SCD_(3) moiety at its 3-position.

Effect of EtOH on the E-Iodohydroxylation of 1,2-Allenylic Sulfoxides with I_(2)

The E-iodohydroxylation of 1,2-allenylic sulfoxides with I2 in the presence of EtOH afforded 3-phenylsulfinyl- 2-iodo-2(E)-alkenols in good yields and regio/stereo-selectivities under very mild conditions.