Transitioning organizations

B-0 and B-C bonds are shorter and stronger than the corresponding Li-O abd Li-C bonds (more covalent character)- therefore tighter more organized transition state. 

This is, of course, an even more highly organized transition state and entails a more negative entropy of activation, but this need not necessarily be prohibitive. 

Ferrocen-l,l -diylbismetallacycles are conceptually attractive for the development of bimetal-catalyzed processes for one particular reason the distance between the reactive centers in a coordinated electrophile and a coordinated nucleophile is self-adjustable for specific tasks, because the activation energy for Cp ligand rotation is very low. In 2008, Peters and Jautze reported the application of the bis-palladacycle complex 56a to the enantioselective conjugate addition of a-cyanoacetates to enones (Fig. 31) [74—76] based on the idea that a soft bimetallic complex capable of simultaneously activating both Michael donor and acceptor would not only lead to superior catalytic activity, but also to an enhanced level of stereocontrol due to a highly organized transition state [77]. An a-cyanoacetate should be activated by enolization promoted by coordination of the nitrile moiety to one Pd(II)-center, while the enone should be activated as an electrophile by coordination of the olefinic double bond to the carbophilic Lewis acid [78],... 

Chiral amines, ArCH(R)NH2, can be prepared by addition of a dialkylzinc to A-(diphenylphosphinoyl)imines, ArCH=N—P(=0)Ph2, using a suitable auxiliary, followed by acid hydrolysis to cleave the phosphorus moiety. A series of 2-azanorbornylmethanols (65) give ee% up to 92%, and they also induce some enantioselectivity in additions to benzaldehyde. A highly organized transition state with two zincs is proposed one coordinates the nitrogens of substrate and catalyst and the other coordinates the oxygens. 

Martini, E.A., Buyer, J.S., Bryant, D.C., Hartz, T.K. and Denison, R.F. 2004. Yield increases during the organic transition improving soil quality or increasing experience Field Crops Research 86 255-266. 

The stereochemistry of the cyclopropyl as well as oxirane moiety in these P-lactams was determined based on the single crystal X-ray analysis of P-lactam 34 and the 4-nitrobenzoyl derivative (37) of 3-hydroxy-P-lactam 32.71 The extremely high diastereoselectivity observed in these cyclopropanation and epoxidation reactions can be explained by taking into account the highly organized transition state structures illustrated in Figure 1. The directing effect of the C-3... 

Showa Denko, JP 62078125,1987, Carbon fibre mfr. in vapour phase — by thermally decomposing organic transition metal cpd., feeding into zone at 1000-1300deg C and adding another organic cpd. Gas... 

Kobko, N. Dannenberg, J. J. Effect of basis set superposition error (BSSE) upon ab initio calculations of organic transition states, 7. Phys. Chem. A 2001, 105, 1944-1950. 

The C-H-acidic position is deprotonated and the resulting C-nucleophile attacks the allylic position. The mode of action has been investigated by Boeckman et al., but it is not yet fully understood. They propose a highly organized transition state (35) which involves a sodium ion as template. The asymmetric center that has been formed in the first step controls the stereochemistry of the new stereogenic center that is built up in this reaction. 

Figure 3.8 Organic transition metal complex dopants used in OLEDs...

Asymmetric induction is thought to arise from an organized transition state in which the chiral amine base is associated with the oxidodiene (ion pairing) and the dienophile (hydrogen bonding, Fig. 31). 

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