Selective bond cleavage

Remarkable solvent effects on the selective bond cleavage are observed in the reductive elimination of cis-stilbene episulfone by complex metal hydrides. When diethyl ether or [bis(2-methoxyethyl)]ether is used as the solvent, dibenzyl sulfone is formed along with cis-stilbene. However, no dibenzyl sulfone is produced when cis-stilbene episulfone is treated with lithium aluminum hydride in tetrahydrofuran at room temperature (equation 42). Elimination of phenylsulfonyl group by tri-n-butyltin hydride proceeds by a radical chain mechanism (equations 43 and 44). 

The terms mode-selective and bond-selective dissociation refer to the control of the dissociation products in VMP. The terms are usually used as synonyms although, strictly speaking, the former should refer to selective preexcitation of a vibrational mode and the latter to the resulting selective bond cleavage. Control of the dissociation products in VMP has been extensively reviewed [28-31] and our discussion will focus on molecules studied (or continued to be smdied) after the latest comprehensive review was published [31], An exception will be a short overview on the VMP of water isotopologues since it was the extensive theoretical and experimental investigations of these molecules, in particular H2O and HOD, that opened a new era of detailed smdies of state-to-state photodissociation out of specific rovibrationally excited states of polyatomic molecules. 

Acyl(phosphido) complexes, with Pt(II), 8, 458 Acyl radicals, via selenium precursors, 9, 477 Acylsilanes, applications, 9, 319 Acylstannanes, preparation, 3, 822-823 l-Adamantyl-2-pyridyl amido complexes, with Zr(IV), 4, 782 Adaptive quantum control, for selective bond cleavage, 1, 247 Addition reactions... 

T. Sato, K. Takahashi, and S. Ichikawa, The selective bond cleavage of D-glucose and D-galactose by the titanium(IV) chloride catalyzed photoreaction, Chem. Lett., (1983) 1589-1592. 

Other bond-cleavage reactions are also important in transition metal-mediated chemical transformations, and a variety of selected bond-cleavage reactions and catalysis are described in this section. 

Scheme 9. Template syntheses with permanently bound templates, (a) Ring extension by insertion and (b) ring expansion by selected bond cleavage.

Recent progress in the synthesis and chemistry of azetidinones 03T7631. Selective bond cleavage of the /1-lactam nucleus in stereocontrolled synthesis 02SL381. 

Mechanism Selective bond cleavage. Cationic polymerization of... 

Adaptive Quantum Control for Selective Bond Cleavage... 

An example of how a proper positioning on the ground state is important in selective bond cleavage is isocyanic acid, HNCO. It has two chemically distinct photodissociation products... 

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