Alkali base-initiated Michael addition/alkyne carbocyclization cascades.

A new cascade reaction involving an intramolecular Michael addition followed by an alkyne carbocyclization is presented. The reaction is promoted by a substoichiometric amount of KHMDS and represents one of the rare examples where the carbocyclization of an unactivated alkyne is mediated by an alkali metal base, under mild conditions. The reaction allows the generation of functionally dense, stereochemically defined, tricyclic structures possessing three adjacent stereocenters in good yields and with high stereoselectivity

Bifunctional organo/metal cooperative catalysis with cinchona alkaloid scaffolds

Cooperative catalysis, inspired by the early findings on enzymatic activation, is a fast growing research area. It refers to the combination of two or more catalytic species that operate together within the same molecular environment to achieve an overall transformation via mutual activation of reaction partners. In this field, cinchona derived scaffolds play a major role. Their combination with a wide range of metal ions and complexes has led to the development of unprecedented transformations in terms or reactivity and stereocontrol. This review discusses recent developments (the last 10 years) in the field of cooperative catalysis using cinchona alkaloid derivatives in combination with metal ions, highlighting the potential of this new research area and the many challenges that still remain for the future. This journal is © 2012 The Royal Society of Chemistry

A new family of cinchona-derived amino phosphine precatalysts: application to the highly enantio- and diastereoselective silver-catalyzed isocyanoacetate aldol reaction.

A new class of readily accessible chiral amino-phosphine precatalysts derived from 9-amino(9-deoxy) epicinchona alkaloids has been developed. In combination with Ag(I) salts, these amino-phosphines performed as effective cooperative Brønsted base/Lewis acid catalysts in the asymmetric aldol reaction of isocyanoacetate nucleophiles. Under optimal conditions, high diastereoselectivities (up to 98%) and enantioselectivities (up to 98%) were obtained

Late-Stage Deoxyfluorination of Alcohols with PhenoFluor

An operationally simple protocol for the selective deoxyfluorination of structurally complex alcohols is presented. Several fluorinated derivatives of natural products and pharmaceuticals have been prepared to showcase the potential of the method for late-stage diversification and its functional group compatibility. A series of simple guidelines for predicting the selectivity in substrates with multiple alcohols is given

Condensed-Phase, Halogen-Bonded CF₃I and C₂F₅I Adducts for Perfluoroalkylation Reactions

A family of practical, liquid trifluoromethylation and pentafluoroethylation reagents is described. We show how halogen bonding can be used to obtain easily handled liquid reagents from gaseous CF3I and CF3CF2I. The synthetic utility of the new reagents is exemplified by a novel direct arene trifluoromethylation reaction as well as adaptations of other perfluoroalkylation reactions

Expedient Route to the functionalized calyciphylline A-type skeleton via a Michael addition-RCM strategy.

An efficient, robust, and scalable strategy to access the functionalized core of calyciphylline A-type alkaloids has been developed starting from commercially available 3-methylanisole. Key features of this approach are an intramolecular Michael addition/allylation sequence and a ring-closing metathesis step