Green Chemistry is a relatively new emerging field that strives to work at the molecular level to achieve sustainability. The field has received widespread interest in the past decade due to its ability to harness chemical innovation to meet environmental and economic goals simultaneously. Green Chemistry has a framework of a cohesive set of Twelve Principles, which have been systematically surveyed in this critical review. This article covers the concepts of design and the scientific philosophy of Green Chemistry with a set of illustrative examples. Future trends in Green Chemistry are discussed with the challenge of using the Principles as a cohesive design system (93 references).

Green Chemistry: Principles and Practice

Collectively, palladium-catalyzed coupling reactions represent some of the most powerful and versatile tools available to synthetic organic chemists. Their widespread popularity stems in part from the fact that they are generally tolerant to a large number of functional groups, which allows them to be employed in a wide range of applications. However, for many years a major limitation of palladium-catalyzed coupling processes has been the poor reactivity of aryl chlorides, which from the standpoints of cost and availability are more attractive substrates than the corresponding bromides, iodides, and triflates. Traditional palladium/triarylphosphane catalysts are only effective for the coupling of certain activated aryl chlorides (for example, heteroaryl chlorides and substrates that bear electron-withdrawing groups), but not for aryl chlorides in general. Since 1998, major advances have been described by a number of research groups addressing this challenge; catalysts based on bulky, electron-rich phosphanes and carbenes have proved to be particularly mild and versatile. This review summarizes both the seminal early work and the exciting recent developments in the area of palladium-catalyzed couplings of aryl chlorides.

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Palladium-Catalyzed Coupling Reactions of Aryl Chlorides

The development of an efficient catalytic activation (cleavage) system for C−H and C−C bonds is an important challenge in organic synthesis, because these bonds comprise a variety of organic molecules such as natural products, petroleum oils, and polymers on the earth. Among many elegant approaches utilizing transition metals to activate C−H and C−C bonds facilely, chelation-assisted protocols based on the coordinating ability of an organic moiety have attracted great attention, though they have often suffered from the need for an intact coordinating group in a substrate. In this Account, we describe our entire efforts to activate C−H or C−C bonds adjacent to carbonyl groups by employing a new concept of metal−organic cooperative catalysis (MOCC), which enables the temporal installation of a 2-aminopyridyl group into common aldehydes or ketones in a catalytic way. Consequently, a series of new catalytic reactions such as alcohol hydroacylation, oxo-ester synthesis, C−C triple bond cleavage, hydrative dime...

Metal-organic cooperative catalysis in C-H and C-C bond activation and its concurrent recovery.

Selective cleavages of carbon-carbon bonds catalyzed by transition-metal complexes have been shown to be increasingly versatile tools for organic synthesis allowing for complementary synthetic strategies Numerous examples of transition-metal catalyzed C-C bond activations of three- and four-membered ring systems have been reported These strained rings have been shown to engage in a variety of new ring-opening rearrangements and cycloaddition reactions leading to valuable structures Besides strain-driven transformations, other facilitating strategies to enforce the C-C bond activation of unstrained molecules have been developed as well While the variety of different transformations is less abundant, they concentrate on chelation-assisted reactions using appropriate permanent or transient directing groups In particular, the cleavage and subsequent functionalization of the C-CN bonds and decarbonylation processes operating by an excision of carbon monoxide from ketone derivatives have witnessed a large progress

A. Sen

Papers

Activation of Unreactive Bonds and Organic Synthesis