Application of the lithiation-borylation reaction to the rapid and enantioselective synthesis of the bisabolane family of sesquiterpenes

The expedient enantioselective synthesis of 5 bisabolane sesquiterpenes has been achieved using a common, one-pot lithiation-borylation reaction of secondary benzylic carbamates and either protodeboronation or oxidation to give the natural products in fewer than 5 steps, with high yield and >94?:?6 er.     

Formic acid electro-synthesis from carbon dioxide in a room temperature ionic liquid

The novel synthesis of formic acid has been achieved in a room temperature ionic liquid via the reaction of electro-activated carbon dioxide and protons on pre-anodised platinum. Only mild reaction conditions of room temperature and 1 atm CO(2) were used. This work highlights the effect of pre-anodisation on Pt surfaces.     

Enantioselective metallo-organocatalyzed preparation of cyclopentanes bearing an all-carbon quaternary stereocenter

Enantioselective metallo-organocatalyzed carbocyclizations of formyl-alkynes have been developed. The cooperation between aminocatalysis and a chiral copper(I) complex granted access to enantio-enriched cyclopentanes through the challenging formation of all-carbon quaternary stereocenters.     

Stereoselective amine-catalyzed carbohydrate chain elongation

Aldol additions of unprotected carbohydrates to 1.3-dicarbonyl compounds have been described. This transformation is based on a dual activation by tertiary amines and 2-hydroxypyridine.     

Hybridization and reaction-based fluorogenic nucleic acid probes

We developed fluorogenic probes, which are photoactivated in the presence of specific nucleic acid templates with the release of fluorescent dyes. This templated reaction can be used to target specific nucleic acids in complex mixtures. We further demonstrate that this reaction can be monitored by single-molecule fluorescence imaging.     

Thioester-isocyanides: versatile reagents for the synthesis of cycle-tail peptides

A novel class of reagents, thioester isocyanides, have been prepared and applied in the synthesis of peptide macrocycles. The isocyanide part of the molecule is deployed in a multicomponent macrocyclization step. This step is followed by chemoselective peptide ligation at the thioester part of the macrocycle. Our method can now be used for rapid assembly and evaluation of cycle-tail peptides.     

Development of a method for the preparation of ruthenium indenylidene-ether olefin metathesis catalysts

The reactions between several derivatives of 1-(3,5-dimethoxyphenyl)-prop-2-yn-1-ol and different ruthenium starting materials [i.e., RuCl?(PPh?)? and RuCl?(p-cymene)(L), where L is tricyclohexylphosphine di-t-butylmethylphosphine, dicyclohexylphenylphosphine, triisobutylphosphine, triisopropylphosphine, or tri-n-propylphosphine] are described. Several of these reactions allow for the easy, in-situ and atom-economic preparation of olefin metathesis catalysts. Organic precursor 1-(3,5-dimethoxyphenyl)-1-phenyl-prop-2-yn-1-ol led to the formation of active ruthenium indenylidene-ether complexes, while 1-(3,5-dimethoxyphenyl)-prop-2-yn-1-ol and 1-(3,5-dimethoxyphenyl)-1-methyl-prop-2-yn-1-ol did not. It was also found that a bulky and strong σ-donor phosphine ligand was required to impart good catalytic activity to the new ruthenium complexes.     

Total synthesis of a glycosylphosphatidylinositol anchor of the human lymphocyte CD52 antigen

The first total synthesis of a glycosylphosphatidylinositol (GPI) anchor bearing a polyunsaturated arachidonoyl fatty acid is reported. This lipid is found in mammalian GPIs that do not undergo lipid remodeling, a process that has important implications in the localization and function of GPI-anchored proteins. Incorporation of the oxidation- and reduction-sensitive arachidonoyl lipid in the target GPI was accomplished by using the para-methoxybenzyl (PMB) group for permanent hydroxyl group protection, which featured a selective, rapid, and efficient global deprotection protocol. The flexibility of this synthetic strategy was further highlighted by the inclusion of two additional GPI core structural modifications present in the GPI anchor of the human lymphocyte CD52 antigen.     

Synthesis of 2,3-syn-diarylpent-4-enamides via acyl-Claisen rearrangements of substituted cinnamyl morpholines: application to the synthesis of magnosalicin

The acyl-Claisen rearrangement of substituted phenylacetyl chlorides and cinnamyl morpholines gives 2,3-syn-diarylpent-4-enamides. Electron-rich cinnamyl morpholines containing alkoxy substituents only reacted with phenylacetyl chlorides; replacement of the phenylacetyl chlorides with alkyl acid chlorides in these reactions gave no rearranged products. Use of the morpholine amides generated in the synthesis of the natural tetrahydrofuran neolignan magnosalicin and tetraphenyl tetrahydrofuran is also reported.