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21.
A dual catalytic decarboxylative allylation and benzylation method for the construction of new C(sp3)–C(sp3) bonds between readily available carboxylic acids and functionally diverse carbonate electrophiles has been developed. The new process is mild, operationally simple, and has greatly improved upon the efficiency and generality of previous methodology. In addition, new insights into the reaction mechanism have been realized and provide further understanding of the harnessed reactivity.A dual catalytic decarboxylative allylation and benzylation method for the construction of new C(sp3)–C(sp3) bonds between readily available carboxylic acids and functionally diverse carbonate electrophiles has been developed. 相似文献
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This paper proves a strong convergence theorem for sequences of pseudo-holomorphic maps from a Riemann surface to a symplectic
manifoldN with tamed almost complex structure. (These are the objects used by Gromov to define his symplectic invariants.) The paper
begins by developing some analytic facts about such maps, including a simple new isoperimetric inequality and a new removable
singularity theorem.
The main technique is a general procedure for renormalizing sequences of maps to obtain “bubbles on bubbles.” This is a significant
step beyond the standard renormalization procedure of Sacks and Uhlenbeck. The renormalized maps give rise to a sequence of
maps from a “bubble tree”—a map from a wedge Σ V S2 V S2 V ... →N. The main result is that the images of these renormalized maps converge in L1,2 ∪C° to the image of a limiting pseudo-holomorphic map from the bubble tree. This implies several important properties of the
bubble tree. In particular, the images of consecutive bubbles in the bubble tree intersect, and if a sequence of maps represents
a homology class then the limiting map represents this class. 相似文献
24.
Simple syntheses of syncarpurea (1) from syncarpic acid and the amino acids ornithine or citrulline are presented. 相似文献
25.
A selective gas chromatographic detector for polynuclear aromatics based on ultraviolet fluorescence
A vapor-phase fluorescence detector for the analysis of mixtures of polynuclear aromatic ring systems has been developed. This system utilizes wide bandpass excitation and wide band emission filters, thus increasing sensitivity and decreasing the complexity of previously designed instruments. The sensitivity of the detector has been demonstrated to be at the nanogram level with reasonable precision. 相似文献
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The room temperature reaction of (Bu4N)3V5O14 with PhPO3H2 in methanol yields the pentanuclear V(V) cluster (Bu4N)[V5O7(OCH3)2(PhPO3)5]·CH3OH (1·CH3OH). In contrast, the hydrothermal reaction of (Ph4P) [VO2Cl2], PhPO3H2 and (NH4)H2PO4 at 125°C for 96 hr yields the mixed valence V(IV)/V(V) species (Ph4P)2[V5O9(PhPO3)3(PhPO3H)2] (3). While the anions of both 1 and 3 exhibit a pentanuclear core, the structural consequences of 1-electron reduction of the fully oxidized cluster of 1 to produce 3 are quite dramatic, including reduction in coordination numbers at two vanadium sites and protonation of two phosphonate oxygen sites with concomitant structural reorganization. Crystal data: 1, monoclinic P21/n,a=12.167(2) Å,b=23.348(5) Å,c=22.508(5) Å,β=98.49(2)°,V=6323.9(19) Å3,Z=4,D calc=1.558 g cm?3; 3, triclinic, $P\bar 1$ ,a=13.478(3) Å,b=14.399(3) Å,c=23.638(5) Å,α=72.53(2)°,β=85.58(2)°,γ=69.88(4)°,V=4107.0(16) Å3,Z=2, Dcalc=1.479 g cm?3. 相似文献
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Gianfranco Denti Mauro Ghedini Jon A. McCleverty Harry Adams Neil A. Bailey 《Transition Metal Chemistry》1982,7(4):222-224
Summary Treatment of [Mo{HB(3,5-Me2C3HN2)3}(NO)I2] with one or two moles of AgPF6 in acetonitrile afforded the paramagnetic (one unpaired electron) complex [Mo{HB(3,5-Me2C3NH2)3}(NO)(NCMe)2][PF6]. The structure of this complex was determined crystallographically, and the six-coordinate geometry of the complex cation confirmed. 相似文献
30.