Odón Arjona

Derivatives of 7-oxabicyclo[2.2.1]heptane in nature and as useful synthetic intermediates

Keywords: Diels-alder-reaction ; opening metathesis polymerization ; acid-catalyzed ; hydrolysis ; lithium aluminum-hydride ; soybean cyst nematode ; diastereoselective bis-hydroxylation ; thromboxane-a2 receptor ; antagonists ; enantioselective total synthesis ; wagner-meerwein ; rearrangements ; platelet-activating-factor Note: Univ Lausanne, Chim Sect, BCH, CH-1015 Lausanne, Switzerland. Ecole Super Phys & Chim Ind, Dept Chim Organ, F-75005 Paris 5, France. Univ Complutense Madrid, Fac Quim, Dept Quim Organ 1, E-28040 Madrid, Spain. Reference LGSA-ARTICLE-1999-014doi:10.1016/S0040-4020(99)00845-5 Record created on 2005-11-09, modified on 2017-05-12

Regioselective domino metathesis of 7-oxanorbornene derivatives as a new stereoselective entry into 2,6-dioxabicyclo[4.3.0]nonenes

Abstract Domino metathesis of allyl- and propargyl-(2-endo-7-oxanorborn-5-enyl) ethers with allyl acetate in the presence of Grubbs’ ruthenium catalyst affords stereoselectively substituted cis-fused bicyclic ethers (2,6-dioxabicyclo[4.3.0]non-8-enes).

The Staudinger reaction of imines derived from 7-oxanorbornenone: formation of spiranic oxazinone versus β-lactam rings

The Staudinger reaction of imines derived from 7-oxanorbornenone with 2-alkoxyacetyl chlorides afforded spiro-β-lactams albeit with an unexpected stereochemistry. This was not the case with arylacetic acid chlorides, which gave rise to spiranic oxazinone rings as well as the expected β-lactams.

Total synthesis of both enantiomers of 15-oxopuupehenol methylendioxy derivatives

Abstract The total synthesis of both enantiomers of puupehenol and 15-oxopuupehenol as methylenedioxy derivatives is described. The key steps of the synthesis are the regioselective transformation of 10 to and the stereoselective cyclization of 12 to 13.

Regio- and stereospecific synthesis of substituted cyclohexenediols from 7-oxabicyclo[2.2.1]hept-5-en-2-ols and organolithium reagents

Abstract The bridge opening reactions of 7-oxabicyclo[2.2.1]hept-5-en-2-ols,4 and6 with organolithium reagents proceed with complete regio- and stereoselectivity to produce highly functionalized cyclohexene derivatives5 and7, respectively.

Regio- and stereocontrolled synthesis of hydroxycyclohexenyl sulfones from oxanorbornenes

Abstract Organolithium reagents and lithium aluminum hydride undergo conjugate additions to oxanorbornenic vinyl sulfones 9-12 with concomitant cleavage of the oxygen bridge, to generate highly functionalized cyclohexenyl phenyl sulfones 13-16 in high yields and in a regio- and stereocontrolled fashion.

Highly diastereoselective bis-hydroxylation of the amino-deoxy-conduritol C ring system. A formal synthesis of the aminocyclitol moiety of the antibiotic Hygromycin A

Abstract A formal synthesis of the aminocyclitol fragment of the antibiotic Hygromycin A is reported using, as a key step, a highly diastereoselective bis-hydroxylation of an amino-deoxy-conduritol C derivative, easily accesible from an 7-oxanorbornenic derivative which in turn can be synthesised from furan.

A convenient approach to the aminocyclitol fragment of pancratistatin from 7-oxanorbornenes

Abstract A totally stereoselective route to an analogue aminocyclitol fragment of the alkaloid pancratistatin has been achieved starting from a 7-oxanorbornenic disulfone. The key step was the alkylative cleavage of the oxygen bridge to produce a highly oxygenated cyclohexenyl sulfone.

Chemoselective protection of thiols versus alcohols and phenols. The Tosvinyl group

Abstract The conjugate addition of aliphatic and aromatic thiols to ethynyl p-tolyl sulphone (tosylacetylene) has been managed to afford Tosvinyl derivatives chemoselectively (in the presence of oxygen nucleophiles) and stereoselectively (isomers Z) in practically quantitative yields. The conditions of choice are: catalytic amounts of Et3N (only 0.5–1.0 mol%), a reaction temperature around 0°C and, for the less acidic thiols, CF3CH2OH or CH3CN/CF3CH2OH as the solvent. Thus, N-Boc-Cys-OMe has been quantitatively protected as its S-Tosvinyl derivative in the presence of N-Boc-Ser-OMe and N-Boc-Tyr-OMe. This novel protecting group is stable to several basic and acidic conditions; its removal is achieved at rt by treatment with an excess of pyrrolidine or at 0°C with alkanethiolate ions.

Reaction of masked o-benzoquinones towards dienophiles with inverse electronic demand. Enol and thioenol ethers as dienophiles

Abstract The Diels-Alder reaction of masked o-benzoquinones and electron-rich dienophiles such as enol ethers and thioenol ethers is described.