Intramolecular Aminolactonization for Synthesis of Furoindolin-2-One

Propellanes are polycyclic compounds in which tricyclic systems share one carbon–carbon single bond. Propellane frameworks that consist of larger sized rings are found in a variety of natural products. As an approach to the stereoselective synthesis of the propellane framework, one of the efficient methods is forming several rings in a single operation. Lapidilectine B (1) is composed of a propellane framework and was synthesized through the oxidative cyclization of trisubstituted alkenes. When the alkene with an ester moiety was treated with N-iodosuccinimide (NIS), iodocyclization proceeded to give the cyclic carbamate. On the other hand, when PhI(OAc)2 was allowed to react in the carboxyl form, a furoindolin-2-one structure corresponding to the A-B-C ring of lapidilectine B (1) was produced. Furthermore, when Pd(OAc)2 catalyst was used for cyclization under oxidative conditions, the product yield was improved.

Cobalt-Tertiary-Amine-Mediated Peroxy-Trifluoromethylation and Halodifluoromethylation of Alkenes with CF2XBr (X = F, Cl, Br) and tert-Butylhydroperoxide

An efficient cobalt-tertiary-amine-mediated peroxy-trifluoromethylation and halodifluoromethylation of alkenes with simple and inexpensive CF2XBr (X = F, Cl, Br) has been described. This method demonstrated broad substrate scope and good to high yields with the tolerance of mono-, di-, and trisubstituted alkenes with both electron-donating and electron-withdrawing groups. The protocol provides an efficient access to various β-peroxyl trifluoromethyl/halodifluoromethyl derivatives. Further transformation of these type of compounds to other useful molecules, such as ketene aminal, α-trifluoromethyl ketone, and gem-difluoroalkene demonstrated the utility of this methodology.

Cobalt-Catalyzed Hydroxyperfluoroalkylation of Alkenes with Perfluoroalkyl Bromides and Atmospheric Oxygen

A mild and efficient method for cobalt-catalyzed hydroxyperfluoroalkylation of alkenes has been developed. This method demonstrated broad substrate scope, good yields, and mild conditions with the tolerance of mono-, di-, and trisubstituted alkenes including both styrenes and non-activated aliphatic olefins. This strategy offered a valuable solution for rapid and efficient construction of β-perfluoroalkyl alcohols using widely available and inexpensive perfluoroalkyl bromides and atmospheric oxygen.

A modular olefination reaction between aldehydes and diborylsilylmethide lithium salts

We describe the preparation of densely functionalised 1,1,-silylborylated trisubstituted alkenes, via boron-Wittig reaction, between LiC(Bpin)2(SiMe3) and aliphatic or aromatic aldehydes. The condensation of diborylsilylmethide lithium salts with α,β-unsaturated aldehydes provides...

Bismuth (III) Triflate: A Mild, Efficient Promoter for the Synthesis of Trisubstituted Alkenes through Knoevenagel Condensation

In this work, smooth efficient and eco-friendly two component coupling method is reported for the synthesis of Knoevenagel Condensation product in presence of Bi(OTf)3 catalyst under solvent free condition. Catalyst has participated in condensation between substituted aldehydes (aromatic and hetero-aromatic) and active methylene compounds (ethyl cyanoacetate, malononitrile and cyanoacetamide) effectively to generate an excellent yield of the product. Bi(OTf)3 catalyst is stable, inexpensive and easily available was used for four times in this reaction without loss of catalytic activity.