M. J. Moolenaar

Synthesis of statine from (S)-malic acid ; stereocontrol via radical cyclization

Abstract Highly stereoselective syntheses of enantiomerically pure γ-amino acids statine and 4- epi -statine from ( S )-malic acid are described by using, respectively, an intramolecular α-acylamino radical reaction and an intermolecular N -acyliminium allylsilane coupling.

Oxazaborolidine catalyzed enantioselective reductions of cyclic meso-imides☆

Abstract A new asymmetric reduction method for meso -imides is reported. Treatment of various imides with a mixture of a chiral oxazaborolidine and BH 3 leads to a mixture of cis - and trans -hydroxylactams and, after subsequent ethanolysis, to the corresponding diastereomerically pure trans -ethoxylactams. The enantiomeric excesses were shown to be 75–89% by both chiral HPLC-determinations and conversion of the reduction products into the corresponding, known lactones.

Application of an organozinc reagent derived from (S)-pyroglutamic acid: a formal synthesis of epibatidine

A formal total synthesis of natural (−)-epibatidine has been developed. Key steps in the synthesis are a copper(I)-mediated coupling of an (S)-pyroglutamic acid-derived organozinc reagent with 1-iodo-3-trimethylsilyl-1-propyne and an N-acyl- or N-sulfonyliminium ion cyclization. Following this route, various N-protected hydroxylactams were converted into 7-azabicylo[2.2.1]heptane derivatives.

Isoprenoid homologation: A synthesis of isoprenoid alcohols using terpene building blocks

Abstract This paper describes the synthesis of linalool and nerolidol by means of a regioselective coupling of the hydroxy-sulfoxide 6a with prenyl-and geranylbromide, followed by reductive desulfurization.

Isoprene functionalization : Hydroxy sulfone terpene building blocks by ring opening of cyclic alkoxy oxosulfonium intermediates

Abstract Hydroxy sulfoxide 1 reacts with SO 2 Cl 2 to give the (Z)-C 5 terpene building block 3b via cyclic alkoxy oxosulfonium salt 2 . The conversion of 1 via the corresponding sulfone 4 leads to the (E) isomer 6b . An explanation is offered for the stereoselective course of the reactions.

Novel approach to trans-fused carbobicycles

Abstract The combination of a silicon directed N-acyliminium ion cyclization reaction and a subsequent S N 2′ substitution of an imide nitrogen with lithium dimethyl cuprate constitutes a novel approach to functionalized transfused carbobicycles.

An effective [1,4]-charge affinity inversion of sulfur functionalized isoprenes

Consecutive [1,2]- and [1,3]-migrations of the sulfur functionality convert the hydroxysulfoxide terpene building block 1a into the charge affinity inverted synthon 6 or the desulfurized chloro aldehyde 9a.

Allenes in Novel Palladium-Catalyzed and Acid-Mediated Cyclization Processes

The unique location of two orthogonal carbon carbon double bonds in the aliene moiety makes this functional group suitable for consecutive (tandem) reactions and the rapid build-up of molecular complexity.1 An addition reaction to one double bond usually leads either to an allylic or a vinylic functional group, or to both, which in several cases leads to enhanced reactivity of the molecule for further processes.