89279-83-4Relevant academic research and scientific papers
Highly diastereoselective Diels-Alder reactions with (R)-ethoxy p-tolyl vinyl sulfonium tetrafluoroborate
Ronan, B.,Kagan, H. B.
, p. 75 - 90 (2007/10/02)
p-Tolyl vinyl sulfoxide has been efficiently activated for the Diles-Alder reactions by transformation into a sulfonium salt 3a or by addition of TMSOTf.Very high diastereomeric excesses have been achieved (>98percent) at -20 deg C in many cases.Best results have been obtained with cyclopentadiene, furan and 2,3-dimethyl-1,3-butadiene.In this way enantiomerically pure oxanorbornenone 19a has been prepared.The reaction mechanism is briefly discussed.
Diels - Alder Reactions of S-Vinyl-S-Arylsulfoximines
Glass, Richard S.,Reineke, Karl,Shanklin, Michael
, p. 1527 - 1533 (2007/10/02)
Cyclopentadiene and the known S-p-tolyl-S-vinyl-N-phthalimidosulfoximine (1a) undergo Diels-Alder reaction to give a mixture of cycloadducts in excellent yield.The structures of the cycloadducts including stereochemistry are assigned by 1H NMR spectroscopy.The crystal and molecular structure of the major cycloadduct 5d, n = 1, G = 1,2 C6H4(CO)2N was determined unequivocally by X-ray crystallographic techniques.Treatment of this major cycloadduct with hydrazine in ethanol resulted in conversion of the sulfoximine to sulfoxide group concomitant with reduction of the carbon-carbon double bond.Use of allyl alcohol as solvent in this reaction allowed conversion to the corresponding unsaturated sulfoxide 8.The previously unknown S-p-tolyl-S-vinyl-N-(p-tolylsulfonyl)-sulfoximine (1b) is somewhat more reactive than phenyl vinyl sulfone and undergoes Diels-Alder reactions with cyclic and acyclic 1,3-dienes in 81-95percent yield.The endo selectivity of vinylsulfoximine 1b is 9:2 with cyclopentadiene and 93:7 with 1,3-cyclohexadiene.With 2-methyl-1,3-butadiene the para adduct is produced regioselectively in a ratio of 4:1.Although formation of the endo adducts from vinylsulfoximine 1b and cyclopentadiene and 1,3-cyclohexadiene is not diastereoselective, the diastereomers can be separated by HPLC.The cycloadducts from 1,3-cyclohexadiene and vinylsulfoximine 1b have been converted to bicyclooct-2-ene and bicyclooct-2-en-5-one.
INVESTIGATION OF A CHIRAL MASKED KETENE SYNTHON. SYNTHESIS OF THE (+)-(1R,4R) and (-)-(1S,4S) ENANTIOMERS OF DEHYDRONORCAMPHOR
Maignan, Christian,Raphael, Ralph A.
, p. 3245 - 3250 (2007/10/02)
The Diels-Alder reaction between (+)-(R)-p-tolyl vinyl sulphoxide and cyclopentadiene gives four separable diastereoisomers.The two most abundant were transformed by a two-step procedure into the two enantiomers of dehydronorcamphor (bicyclohept-5-
