A stereoselective cyclization between alkylidene oxindoles and 5-methoxyoxazoles has been developed using catalytic titanium(IV) chloride (as low as 5 mol %) to afford spiro[3,3'-oxindole-1-pyrrolines] in excellent yield (up to 99%) and diastereoselectivity (up to 99:1). Using a chiral scandium(III)-indapybox/BArF complex affords enantioenriched spirooxindole-1-pyrrolines where a ligand-induced...

We document a route for the synthesis of a densely functionalized spiro-fused 2,5-cyclohexadienone as an intermediate for the synthesis of resineferatoxin. The strategy is based on an unprecedented diastereoselective, intramolecular phenol para-alkylation to a cross-conjugated cyclohexadienone. In the course of these synthetic studies we developed rapid access to a chiral nitrile possessing a q...

The title compound, C19H16F4O4, was prepared by the condensation reaction of 2,6-di-fluoro-benzaldehyde and penta-erythritol. The whole mol-ecule is generated by twofold rotational symmetry. The two six-membered O-heterocycles adopt chair conformations through a shared spiro-carbon atom that is located on the crystallographic twofold rotation axis. In this conformation, the two aromatic rings a...

Asymmetric synthesis of drug-like functionalized spiro[chroman-3,3'-indolin]-2'-ones 5 containing three contiguous stereocenters with high diastereo- and enantioselectivities was achieved using the reflexive-Michael (r-M) reaction of unmodified hydroxyenals 1 with various (E)-3-alkylideneindolin-2-ones 2 in the presence of (R)-DPPOTMS/AcOH (R)-3/4b as a catalyst at room temperature. Chiral spir...

The privileged spiro[pyrrolidin-3,3'-oxindole] derivatives exhibit important biological activities. An enantioselective organocatalytic approach to the rapid synthesis of spiro[pyrrolidin-3,3'-oxindole] derivatives with high enantiopurity and structural diversity is described. The asymmetric catalytic three-component 1,3-dipolar cycloaddition of a broad range of methyleneindolinones with aldehy...

Facile aerial oxidation is a general feature of guanine ribo- and 2'-deoxyribonucleosides that are substituted at the 8-position by an aminoaryl group. In previous work, it had been suggested that two of the major oxidation products are a pair of diastereomers having a spiro structure. These were presumed to be related by a chiral difference at the spiro carbon atom. The pattern of the oxidativ...

An enantioselective phosphine-catalyzed transformation has been developed for the synthesis of chiral cyclobutene triesters and fluorinated spirocyclic compounds. The strategy involved a P(III)/P(V) redox cycling process, via in situ reduction phosphine oxide with phenylsilane. This catalytic methodology enabled functionalized cyclobutenes (24 examples, up to 94% ee). On occasion extension this...

In the present work, we describe a convenient synthesis of spiro-fused D-fructo- and D-psico-configurated oxazoline ligands and their application in asymmetric catalysis. The ligands were synthesized from readily available 3,4,5-tri-O-benzyl-1,2-O-isopropylidene-β-D-fructopyranose and 3,4,5-tri-O-benzyl-1,2-O-isopropylidene-β-D-psicopyranose, respectively. The latter compounds were partially de...