86558-54-5Relevant academic research and scientific papers
Enantiocontrolled synthesis of quaternary carbon centers via anionic oxy-cope rearrengement: An efficient synthesis of (+)-dihydromayurone
Lee, Eun,Shin, In-Jae,Kim, Tae-Seong
, p. 260 - 264 (2007/10/02)
(+)-Dihydromayurone (1) was enantioselectively synthesized from β-cyclocitral (7). The key step in the synthesis involved anionic oxy-Cope of allylic alcohol 6 to aldehyde 5. Efficient transfer of chirality from the secondary allylic alcohol center to the quaternary carbon center was observed vai chairlike transition state with the equatorial oxyanionic bond.
A New General Synthetic Approach to Diterpenes: Application to Syntheses of (+ -)-Taxodione and (+ -)-Royleanone.
Engler, Thomas A.,Sampath, Umashanker,Naganathan, Sriram,Velde, David Vander,Takusagawa, Fusao
, p. 5712 - 5727 (2007/10/02)
High-pressure Diels - Alder reactions of 1,3,3-trimethyl-2-vinyl-1-cyclohexenes 3a,b,i with substituted 1,4-benzoquinones afford, in good yield, highly functionalized tricyclic ring systems which are found in many classes of naturally occuring terpenes.Notably, the reactions of 3a are highly regio- and stereoselective.Efficient, formal syntheses of antitumor diterpenes (+ -)-taxodione and (+ -)-royleanone are reported, which demonstrate the practical application of this new strategy for the preparation of varied terpene systems.Of particular interest is that the high-pressure reactions are accelerated by mild Lewis acids and the regio- and stereoselectivity of these reactions is also improved under the combined high-pressure / Lewis acid conditions in comparison to the high-pressure conditions alone.Indeed, in the reaction of 3a with 2-methoxy-5-methyl-1,4-benzoquinone, ZnBr2 is required to effect the Diels-Alder reaction even at 12 kbar, and endo adduct 12c is formed stereoselectively in 90percent yield.In contrast, low-temperature Ti(IV)-catalyzed reactions of diene 3a with methoxy-substituted 1,4-benzoquinones at atmospheric pressure regioselectively produce dihydrobenzofurans 19 and 20, apparently via alkylation of the quinone Ti(IV) complex by the diene followed by the ring closure.
SYNTHESE TOTALE DU (+/-)POLIGODIAL, DE LA DRIMENINE ET DE COMPOSES APPARENTES A JONCTION DE CYCLE cis ET trans
Jalali-Naini, M.,Guillerm, D.,Lallemand, J-Y.
, p. 749 - 758 (2007/10/02)
Isomerization by base under kinetic or thermodynamic control of the Diels-Alder adduct of 1,3,3-trimethyl-2-vinyl-1-cyclohexene with dimethyl acetylene dicarboxylate leads to two isomers which, after catalytic hydrogenation, give in high yield starting materials for synthesis of trans and cis drimanes.A short total synthesis of (+/-)-polygodial and (+/-)-drimenine from one of these isomers is desribed.
The Diels-Alder Route to Drimane related Sesquiterpenes; Synthesis of Cinnamolide, Polygodial, Isodrimeninol, Drimenin and Warburganal
Hollinshead, David M.,Howell, S. Christopher,Ley, Steven V.,Mahon, Michael,Ratcliffe, Norman M.,Worthington, Paul A.
, p. 1579 - 1589 (2007/10/02)
The stereospecific preparation of various 1-vinyl-2,6,6-trimethylcyclohex-1-enes (6) as potential diene precursors in the Diels-Alder reaction with dimethyl acetylenedicarboxylate have been investigated.The reaction of the parent diene (6a) with dimethyl acetylenedicarboxylate affords an adduct (18) in 94percent yield.This species was reductively isomerised using 10percent Pd/C/H2 and a mineral acid to give a trans-fused decalin diester (19).Reduction of (19) with lithium aluminium hydride afforded 1,4,4a,5,6,8,8a-octahydro-5,8,8a-trimethyl-1β,4aα,8aβ-naphthalene-1,2-dimethanol (24) a key starting material for the highly efficient syntheses of five drimane sesquiterpene natural products, cinnamolide (1), polygodial (2), isodrimeninol (3), drimenin (4), and warbuganal (5).Microbial oxidation reactions using C. elegans or A. niger of (2), (24), and (1) gave good yields of the corresponding 3β-hydroxy derivatives, (30), (31), and (32).Several other unusually substituted drimane derivatives are reported.
