Some Recent Preparative Chemistry

Some recent preparative chemistry of protactinium. D. Brown, Adv. Inorg. Chem. Radiochem., 1969, 12, 1-51 (138). 

Some Recent Preparative Chemistry of Protactinium D. Brou n... 

We 11 begin by describing the preparation and properties of p keto esters proceed to a discussion of their synthetic applications continue to an examination of related species and conclude by exploring some recent developments m the active field of synthetic car banion chemistry... 

We have recently prepared some new and very thermolabile CO- and N2 comPlexes derived from titanocene [1] or decamethyltitanocene [2], and have characterized them by their vibrational spectra. As well as "classical" matrix spectroscopy, we have used spectroscopy in liquid xenon (LXe). The application of chemistry and methodology indicates the decamethylsilicocene structure, which represents the first example of a stable jt-complex of divalent silicon [3]. Reaction with CO or N2 leads to the two title complexes [4] ... 

This chapter has discussed the transition metal-catalyzed synthesis of allenes. Because allenes have attracted considerable attention as useful synthons for synthetic organic chemistry, effective synthetic methods for their preparation are desirable. Some recent reports have demonstrated the potential usefulness of optically active axially chiral allenes as chiral synthons however, methods for supplying the enantiomerically enriched allenes are still limited. Apparently, transition metal-catalyzed reactions can provide solutions to these problems. From the economics point of view, the enantioselective synthesis of axially chiral allenes from achiral precursors using catalytic amounts of chiral transition metal catalysts is especially attractive. Considering these facts, further novel metal-catalyzed reactions for the preparation of allenes will certainly be developed in the future. 

Although this monograph is concerned primarily with compounds containing one phosphorus atom, some account has already been given of esters of pyrophosphoric acid (p. 103) attention must also be drawn to some recent important contributions to the organic chemistry of polyphosphorus compounds made by M. Tolkmith. He has prepared decamethyltriphosphor-amide1 (XX) by the action ... 

Eight procedures highlighting some recent and practical developments in organometallic chemistry form the next group. Highly reactive calcium prepared by reduction of dissolved calcium bromide with lithium biphenylide affords access to the... 

In this section, some recent uses of pyrans in synthesis are described. Much of the chemistry of this class of compounds involves Diels-Alder cycloadditions, metal- and thermal-assisted reorganization reactions, and the preparation and reactions of organometallic derivatives. The chemistry of the pyrylium salts, useful precursors to substituted aromatics (B-64MI11600), will not be discussed here. 

Why then write another review on the (helium I) photoelectron spectroscopy of silicon compounds At a time of rapidly increasing computer application to various aspects of preparative chemistry, it seems worthwhile to summarize historic and more recent achievements in the rapidly progressing knowledge of silicon-containing molecules, and their molecular state properties, which are via Koopmans theorem intimately connected to quantum chemical calculations. Above all, some selected cases are well-suited to illustrate... 

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