Michinori Karikomi

Synthesis of chiral [5]helicenes using aromatic oxy-Cope rearrangement as a key step

Abstract Both enantiomers of ( P )-(+)-2- and ( M )-(−)-2-acetoxy-11,14-dimethyl[5]helicenes 8 were synthesized by asymmetric aromatic oxy-Cope rearrangement of the corresponding chiral bridged bicyclic compounds, which were obtained by enzymatic resolution. The absolute configurations of 8 were assigned by their circular dichroism spectra.

Synthesis of 2-acetoxy[5]helicene by sequential double aromatic oxy-Cope rearrangement

Abstract Synthesis of 2-acetoxy[5]helicene has been achieved by sequential double aromatic oxy-Cope rearrangement strategy. Combination of 1-methoxybicyclo[2.2.2]oct-5-en-2-one and p -bromophenylmagnesium bromide gave 3-bromophenanthrene through several steps including an aromatic oxy-Cope rearrangement as a key step. The second oxy-Cope rearrangement and the following transformation gave 2-acetoxy[5]helicene by similar procedure.

Synthesis of tetrahydrofurans by regio- and stereoselective cyclization of epoxyalcohols using magnesium halide

Abstract A novel synthetic method for several tetrahydrofuran derivatives by intramolecular cyclization of epoxyalcohols is described. The presence of a catalytic amount of magnesium halide altered the regio- and stereoselectivity of the cyclization reaction.

Stereoselective synthesis of 3-hydroxyazetidines via regioselective halogenation of 2,3-epoxyamines by using magnesium bromide

Abstract A novel stereoselective synthesis of 3-hydroxyazetidines starting from 2,3-epoxyamines is described. Regioselectivity of the intramolecular cyclization of 2,3-epoxyamines is controlled by the use of magnesium bromide. The cyclization proceeds with retention of the stereochemistry, caused by double inversion of two sequential S N 2 reactions of the epoxyamines.

Synthesis of 1-alkyl-3-hydroxy-2-phenylazetidines

Several (R * ,S * )-1-alkyl-3-hydroxy-2-phenylazetidines (1) were synthesized by the reaction of (R * ,R * )-2-(1-bromobenzyl)oxirane (2a) with aliphatic primary amines in good yields. By the reaction of (R * ,S * )-2-(1-bromobenzyl)oxirane (2b), only (R * ,R * )-2-aminomethyl-3-phenyloxirane (3) was obtained. Also, the reaction of (R * ,R * )-2-(1-bromobenzyl)-2-methyloxirane (2c) gave a mixture of (R * ,S * )-3-hydroxy-3-methyl-2-phenylazetidine (4) as the major product and (R * ,S * )-2-aminomethyl-2-methyl-3-phenyloxirane (5) as the minor product

Chiral sensing for amino acid derivative based on a [2]rotaxane composed of an asymmetric rotor and an asymmetric axle.

A racemic [2]rotaxane, composed of an asymmetric rotor and an asymmetric axle, formed a diastereomer with an amino acid derivative, and showed an optical response for the chiral recognition.

A novel crownophane trapping CO2 as carbonic acid at room temperatureElectronic supplementary information (ESI) available: synthesis of compounds, 2 ? 4, and the data of their 1H NMR, IR, ESI mass spectra and elemental analysis, and the charts of IR spectrum and DTA and TGA thermograms of the solids separated out after bubbling CO2. See http://www.rsc.org/suppdata/cc/b4/b403152k/

A 25 membered crownophane with two hydroxy and two amide groups around the cavity has been reported for the first time to be able to include carbonic acid formed from both carbon dioxide and water molecules to give a stable 1:1 complex at room temperature.

The first total synthesis of (±)-2-thiocyanatoneopupukeanane based on a pinacol-type rearrangement

The racemic mixture of 2-thiocyanatoneopupukeanane, a marine sesquiterpene-thiocyanate with a tricylo[4.3.1.03,7]decane skeleton, was prepared through a pinacol-type rearrangement of a bicyclo[2.2.2]oct-5-en-2-ol giving a bicyclo[3.2.1]oct-6-en-2-one derivative and an aldol reaction leading to the neopupukeanane framework.

Synthetic study of bicyclo[5.2.1]dec-8-en-4-ones based on tandem anionic [1,3] and oxy-Cope rearrangements of 2-vinylbicyclo[3.2.1]oct-6-en-2-ols

An efficient one-pot synthesis of a 10,10-ethylenebicyclo[5.2.1]dec-8-en-4-one derivative, which can be considered as a synthetic intermediate for the taxane skeleton, has been achieved by tandem anionic [1,3] and oxy-Cope rearrangements of 2-vinylbicyclo[3.2.1] oct-6-en-2-ol.

A novel method for the synthesis of diquinanes based on anionic [1,3] rearrangement of bicyclo[3.2.1]oct-6-en-2-ols

Abstract The synthesis of unique diquinanes, possessing four continuous methyl groups on the convex of the diquinane skeleton, has been achieved by employing a combination of pinacol-type rearrangement and efficient anionic [1,3] rearrangement strategies.