76337-97-8Relevant academic research and scientific papers
Stereochemical Control in the Ester Enolate Claisen Rearrangement. 2. Chairlike vs Boatlike Transition-State Selection
Ireland, Robert E.,Wipf, Peter,Xiang, Jia-Ning
, p. 3572 - 3582 (2007/10/02)
The preference for chair-and boatlike transition-state geometries in the ester enolate Claisen rearrangement of straight chain, carbocyclic, and heterocyclic propanoates was investigated.A novel stereoelectronic effect in pyranoid and furanoid glycal systems leads to a significant relative stabilisation of the boatlike vs the chairlike TS(excit.).The preferred transition state in six- and five-membered carbocyclic systems is highly dependent on steric factors, as the energy difference between chair-and boatlike TS(excit.) tends to be small.With straight-chain substrates, a significant contribution of the boatlike TS(excit.) to the rearrangement product mixture is only expected in bis-donor substituted allylic esters.
Azaprostacyclins, their preparation and pharmaceutical use
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, (2008/06/13)
Azaprostacyclins of Formula I STR1 wherein R1 is hydrogen, alkyl, cycloalkyl, aryl, a heterocyclic residue, or a phenacyl residue optionally substituted on the phenyl ring by bromine, phenyl, alkoxy, or dialkoxy, W is a free or functionally modified carbonyl group or a STR2 wherein R8 is hydrogen or alkyl of 1-5 carbon atoms and R9 is hydrogen or a readily cleavable ether or acyl residue and wherein the OR9 -group can be in the α- or β-position, R2 is a free or functionally modified hydroxy group.
TRICYCLO2,8>OCTANONES AS BUILDING BLOCKS IN NATURAL PRODUCTS SYNTHESIS (I). --THE SYNTHESIS OF CHRYSOMELIDIAL--
Kon, Kenji,Isoe, Sachihiko
, p. 3399 - 3402 (2007/10/02)
The stereocontrolled synthesis of chrysomelidial from 4-methyl-tricyclo2,8>octan-3-one is described.
