Corinne Comoy

Enantioselective synthesis of (+)-3-oxabicyclo[3.2.0]hept-6-en-2-one

Abstract The title compound was obtained in 99.3% ee by enzymatic oxidation of cis -2-cyclobutene-1,4-bis(hydroxymethyl) in the presence of horse liver alcohol dehydrogenase. Another route was through desymmetrisation of cis -cyclobut-3-ene-1,2-dicarboxylic anhydride with (−)-pantolactone.

New efficient synthesis of α-hydroxyesters from carbonyl compounds via α-chloroglycidic esters

Abstract The chain extension with an α-hydroxyester unit of various carbonyl compounds was realized, in two steps, via α-chloroglycidic esters. Synthesis, results and expected mechanisms are reported.

Synthesis of P-chiral enephosphonic acid derivatives

Abstract An efficient and convenient synthesis of chiral enephosphonic acid derivatives (enephosphonates, enephosphonamides, enephosphinates) was reported by a two-step procedure involving alkylidenediphosphorylation of nucleophiles followed by a Horner–Emmons olefination. Depending on the selected strategy, the synthesis could be executed according to a one-pot or a two-step reaction sequence. Regioselectivity of Horner–Emmons reaction and 31 P-NMR study of diphosphorylated anions were described.

Improved Condensation of 2-pyridyllithium Intermediates with Aldehydes: Application for the Synthesis of 2-(polyhydroxyalkyl)pyridines

The scope and the limitations of 3-chloro-2-pyridinyl lithium condensation to aldehydes were envisioned de- pending on metallation conditions or condensation time and temperatures. The procedure was applied to various aromatic, aliphatic or functionalized aldehydes to afford a new and efficient access to 2-(polyhydroxyalkyl)pyridines. n Scheme 1. Selective functionalization of 3-chloropyridine induced by (n-BuLi/LiDMAE) superbase. In this previous study, we described the regioselective C- 2 functionalization of 3-chloropyridine (2) performed by a metallation at -60°C for 1h, in hexane as solvent, with super- base (n-BuLi/LiDMAE) (3 eq). Condensation reactions were afforded using various representative electrophiles, one was a carbonyl reagent (tBuCHO, 60% isolated yield). In agree- ment with these results, we reported here a detailed investi- gation to extend the scope of this condensation using a vari- ety of functionalized aldehydes. The best determined condi- tions led us to define an improved protocol for introducing polyhydroxylated moieties on pyridinic ring allowing the synthesis of 1a-b.

CHAPTER 10:NHC–Nickel and Platinum Complexes in Catalysis

This Chapter summarizes the recent impact that the use of N-heterocyclic carbene (NHC) ligands in the field of Ni- and Pt-mediated processes.This family of ligands have allowed for the development of novel nickel-based catalysts of increased reactivity and selectivity compared to previous Ni-phosphine reagents. These NHC–Ni reagents are active in hydrogenation, hydrogen transfer properties and C–S or C–F bond activation. Conversely, they efficiently catalyze arythiolation, hydrothiolation and cross-coupling reactions as well as different cross-couplings, cycloadditions of alkynes or isomerization of vinylcyclopropanes.On the other hand, NHC–Pt analogues have been less studied for catalytic applications. Regioselective and/or asymmetric hydroboration as well as hydrosilylation constitute the two most areas of research for these species.