Abstract Starting from (+)‐camphor‐10‐sulfonyl chloride ( 5 ), the crystalline sultam 8 was easily prepared. Lewis ‐acid‐promoted Diels‐Alder additions of N ‐acry‐loyl and ‐crotonoyl derivatives 9 10 , respectively, to cyclopentadiene 1,3‐butadiene at −130 −78° furnished adducts 11 12 17 with high chiral efficiency. Crystallization nondestructive removal gave either alcohols 13 14 18 ir acid 19 in 99% enantiomeric purity. The sense induction reversed on using enantiomer as auxiliary....

Abstract Starting from the enantiomerically pure monoterpenes (+)‐pulegone ( 3 ), (+)‐limonene 7 (−)‐β‐pinene 9 (+)‐ and (−)‐camphor 13 ) or (+)‐cholestenone 11 chiral alcohols 4, 5, 6, 8, 10, 12, 14, 15, 16, 17 et 18 were prepared; their acrylates II underwent a TiCl 4 ‐promoted Diels‐Alder addition to cyclopentadiene (Scheme 3, Table) giving in predictable manner either (2 R )‐ S )‐adducts III with 63 88% asymmetric induction.

Abstract One‐pot Diels ‐ Alder reactions of cyclopentadiene with 3‐crotonoyl‐ ( 2 ) and 3‐acryloyl‐4,4‐dimethyl‐1,3‐oxazolidin‐2‐one 3 ), Mediated by chiral Lewis acids, are described. AlCl , EtAlCl Et AlCl, TiCl 4 ZrCl SnCl SiCl BBr modified derivatives D ‐mannitol, L ‐tartaric acid, R )‐binaphthol, were applied as promotors. The reaction dienophile carried out in CH Cl at −78° high yield, was characterized excellent π‐face selectivity. In case the efficiency chirality transfer much lower.

Abstract Starting from (+)‐ or (−)‐camphor, the antipodal alcohols 14 and 18 , respectively, have been prepared; corresponding acrylates 15 19 underwent TiCl 2 (i‐PrO) ‐mediated Diels ‐ Alder additions to cyclopentadiene give adducts 20a 22a with 95 % endo 99.2% πpH‐face selectivities. Adduct was converted enantiomerically pure norbornenone 26 . Addition of 1,3‐butadiene acrylate in presence 4 afforded 3‐cyclohexenyl carboxylate 29 > 95.6 stereodifferentiation. The ‐promoted [4 + 2]...

For the asymmetric isomerization of geranyl- or neryldiethylamine ((E)- (Z)-1, resp.) and allyl alcohols geraniol nerol (Z)-2, to citronellal (4) in presence a [RhI(ligand)cycloocta-1,5-diene)]+ catalyst, atropic ligands 5 – 11 are compared under homogeneous polymer-supported conditions with non-C2-symmetrical diphosphino ferrocene 12 16. The tBu-josiphos ligand 13 daniphos 19, available both antipodal series, already catalyse reaction (E)-1 at 20° (97% e.e.) favourably compare binap (see...

The rich chemistry of East Indian Sandalwood oil has fascinated chemists for over a century. Whilst the synthesis on industrial scale principal odour vector (–)‐(Z)‐β‐Santalol 2, resisted all attempts to date, many closely related fragrant sandalwood ingredients have been discovered and manufactured scale. This precious wood is still listed as endangered appears CITES red list, despite an increased number plantations being developed. review will focus interesting Santalum album (Linn.)...

Abstract Starting from sultam 1 , the chiral dienophile (2 R )‐ N ‐glyoxyloylbornane‐10,2‐sultam ( 4 ) was readily prepared. Non‐catalyzed atmospheric‐ and high‐pressure as well [Eu(fod) 3 ]‐promoted [4 + 2] cycloadditions of 1‐methoxy‐buta‐1,3‐diene 5 to leading with high asymmetric induction 6‐methoxy‐3,6‐dihydro‐2 H ‐pyran‐2‐yl derivatives 6 – 9 are described. The extent direction in these reactions were established by H‐NMR analysis chemical correlation, respectively. Stereochemical...

Summary Invasion of aqueous drilling, completion, or fracturing fluids can reduce the relative permeability to gas and thereby causes a water block. In case low-permeability formations, capillary pressure tends be high because small pore size. Cleanup blocks requires drawdown unless vaporization by flowing is improved using specific additives such as alcohols. The purpose this work investigate fracture-face damage measuring relevant petrophysical parameters: absolute-permeability return...

Abstract In connection with structure‐activity relationship studies, analogues of campholenal ((+)‐ 4b ), an important building block for sandalwood‐like odorants, were prepared. The five‐membered‐ring 4 obtained by epoxidation the corresponding α‐pinene derivatives 2 , followed catalytic ZnBr isomerisation ( Scheme ). six‐membered‐ring skeleton was ozonolysis α‐campholenyl acetate ((−)‐ 14b intramolecular aldol condensation 5 13 C‐NMR assignments are given.

Abstract An internal historical point of view is presented on the discovery and development both methyl jasmonate its saturated analogue Hedione ® . A discussion synthetic approaches performed during last decade, structureactivity relationships analogous structures are also presented.

ABSTRACT Dynamic mixtures of aminals generated by reversible reaction diamines with volatile aldehydes and ketones are suitable delivery systems to increase the long‐lastingness fragrance perception in functional perfumery applications. N ‐Heteroarylmethyl‐substituted secondary 1,2‐diaminocyclohexane, 1,3‐diaminocyclohexane, 1,2‐diaminoethane, 1,2‐diaminopropane, 1,3‐diaminopropane or 2‐(aminomethyl)piperidine were prepared furan‐, 1 H ‐pyrrole‐, thiophene‐ pyridine‐2‐carbaldehyde reduction...

Abstract The exocyclically unsaturated conjugated keto esters 10 , obtained via a Claisen ortho ester rearrangement of the allylic hydroxy ketones 9 were either directly hydrogenated or partially isomerized into endocyclically tetrasubstituted didehydrojasmonoid intermediates 14 prior to more selective hydrogenation with Pd/C in cyclohexane disubstituted oxocyclopentaneacetates 15 ( Scheme 2 ). key by four‐step sequence, including acetal protection/deprotection from enone 1 specific case...

Oyster leaf (Mertensia maritima), also called vegetarian oyster, has a surprising oyster-like aroma. Its volatile composition was investigated here for the first time. In total, 109 compounds were identified by gas chromatography-mass spectrometry (GC-MS) and quantified GC-FID. The use of GC-olfactometry on both polar nonpolar columns allowed detection molecules having an oyster-like, marine odor. Four confirmed synthesis: (Z)-3-nonenal, (Z)-1,5-octadien-3-ol, (Z,Z)-3,6-nonadienal,...

Abstract Starting from (+)‐camphor‐10‐sulfonic acid (1) the chiral crystalline alcohols 3 and 11 were prepared in two steps. Lewis ‐acid‐mediated [4+2]‐additions of their acrylates to 1,3‐dienes studied. Notably, acrylate 4 underwent TiCl 2 (OiPr) ‐promoted Diels ‐ Alder addition cyclopentadiene giving after recrystallization efficiently pure (2 R )‐adduct 5 .

A correlation between the solvent polarity and logarithm of diastereoisomer ratio (dr) was found for uncatalyzed [4+2] cycloaddition cyclopentadiene to N,N′-fumaroyldi[(2R)-bornane-10,2-sultam]. Using Abboud-Abraham-Kamlet-Taft parameters, predictive values this method, allowed an optimum diastereoisomeric excess (de) 96% (EtOH, −78°). similar diastereoselectivity achieved using 5M LiClO4/Et2O or H2O/β-cyclodextrin, influence supercritical CO2 is also reported. Selective cycloadditions...

Abstract α‐, β‐, and γ‐Irones analogues have been prepared from optically active ketones (+)‐ 1 , 6a,b 17 via a Corey‐Chaykovsky oxiranylation (Me 2 S, Me SO 4 SO, NaOH) followed by isomerisation (SnCl or MgBr ). (+)‐Dihydrocyclocitral ( 19a ), obtained (−)‐citronellal, analogue 19b were condensed with various to afford 21a–f after hydrogenation 22a–f. A mild oxidative degradation of aldehydes trans ‐and (−)‐ cis ‐ 8a,b 16a,b as well olfactive evaluations, 13 C‐NMR assignments, absolute...

The highly diastereoselective [4 + 2] cycloaddition of 1-methoxybuta-1,3-diene (3) to (2R)-N-glyoxyloylbornane-10,2-sultam (2) afforded the adduct (4) which was effectively transformed into (4R,6S)-4-hydroxy-6-hydroxymethyltetrahydro-2-pyrone (1), a key synthon for lactone moiety compactin and mevinolin.

Abstract Comparative semi‐empirical PM3 and ab initio STO 3‐21G calculations on bornanesultam‐derived dienophiles containing the structural moiety SO 2 NC(O)X(α) = Y(β) suggest that, among conformers of low energy, thermodynamically less stable /C(O)‐ syn ,C(O)/X=Y‐s‐ cis conformation is also reactive in terms LUMO level atomic coefficients. Furthermore, X(α), coefficients are nonequivalent with respect to both X(α)‐re X(α)‐ si faces, thus have, depending conformation, a matching or...