19945-61-0Relevant articles and documents
Olefination of activated halides and mesylates using arsonium ylides
Seyer, Andre,Alcaraz, Lilian,Mioskowski
, p. 7871 - 7874 (1997)
Alkyltriphenylarsonium ylides react with activated primary halides and mesylates to afford olefins in good yields and with high E-selectivity.
Biosynthesis of C11 and C16 homoterpenes in higher plants; stereo- chemistry of the C-C-bond cleavage reaction
Boland, Wilhelm,Gaebler, Andreas,Gilbert, Matthias,Feng, Zhuofu
, p. 14725 - 14736 (1998)
In higher plants the C11 homoterpene 4,8-dimethylnona-1,3,7-triene (1) originates from oxidative degradation of nerolidol (3) or geranylacetone (4). The geometry of the transition state of bond cleavage has been shown to be syn-periplanar, for both 3 and 4 by application of chirally labelled, deuterated precursors to flowers of Magnolia liliiflora nigra or leaves of the Lima bean Phaseolus lunatus. The synthesis of the deuterated, chiral metabolic probes 3 and 8 from nor-farnesene (5), via the enantiomeric epoxides (2S,3R)-6 and ent-6, is described.
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Negishi,E. et al.
, p. 2254 - 2256 (1978)
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Highly Selective and Catalytic Generation of Acyclic Quaternary Carbon Stereocenters via Functionalization of 1,3-Dienes with CO2
Chen, Xiao-Wang,Zhu, Lei,Gui, Yong-Yuan,Jing, Ke,Jiang, Yuan-Xu,Bo, Zhi-Yu,Lan, Yu,Li, Jing,Yu, Da-Gang
, p. 18825 - 18835 (2019/11/28)
The catalytic asymmetric functionalization of readily available 1,3-dienes is highly important, but current examples are mostly limited to the construction of tertiary chiral centers. The asymmetric generation of acyclic products containing all-carbon quaternary stereocenters from substituted 1,3-dienes represents a more challenging, but highly desirable, synthetic process for which there are very few examples. Herein, we report the highly selective copper-catalyzed generation of chiral all-carbon acyclic quaternary stereocenters via functionalization of 1,3-dienes with CO2. A variety of readily available 1,1-disubstituted 1,3-dienes, as well as a 1,3,5-triene, undergo reductive hydroxymethylation with high chemo-, regio-, E/Z-, and enantioselectivities. The reported method features good functional group tolerance, is readily scaled up to at least 5 mmol of starting diene, and generates chiral products that are useful building blocks for further derivatization. Systemic mechanistic investigations using density functional theory calculations were performed and provided the first theoretical investigation for an asymmetric transformation involving CO2. These computational results indicate that the 1,2-hydrocupration of 1,3-diene proceeds with high π-facial selectivity to generate an (S)-allylcopper intermediate, which further induces the chirality of the quaternary carbon center in the final product. The 1,4-addition of an internal allylcopper complex, which differs from previous reports involving terminal allylmetallic intermediates, to CO2 kinetically determines the E/Z- and regioselectivity. The rapid reduction of a copper carboxylate intermediate to the corresponding silyl-ether in the presence of Me(MeO)2SiH provides the exergonic impetus and leads to chemoselective hydroxymethylation rather than carboxylation. These results provide new insights for guiding further development of asymmetric C-C bond formations with CO2
Catalytic enantioselective 1,2-diboration of 1,3-dienes: Versatile reagents for stereoselective allylation
Kliman, Laura T.,Mlynarski, Scott N.,Ferris, Grace E.,Morken, James P.
, p. 521 - 524 (2012/03/11)
More with boron: The development of catalytic enantioselective 1,2-diboration of 1,3-dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1-disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized homoallylic alcohol products. Copyright