C bonds formation synthesis

Busato S, Scheffold R (1994) Vitamin B12 catalyzed C-C bond formation synthesis of Jasmonates via sequential radical reaction. Helv Chim Acta 77 92-99... 

F. Debart, J-J. Vasseur, Y.S. Sanghvi, and P.D. Cook, Intermolecular radical C-C bond formation synthesis of a novel dinucleoside linker for non-anionic antisense oligonculeosides. Tetrahedron Lett. 33 2645 (1992). 

D. Seebach, R. Imwinkelried, and T. Weber, EPC Synthesis With C,C Bond Formation via Acetals and Enimines, in Modern Synthetic Methods 1986, Vol. 4, R. Scheffold, Ed., Springer-Verlag, New York, 1986, p. 125. 

Contribution of Prof. D. A. Evans to stereoselective synthesis of heterocycles with C—C bond formation (self-review) 99T8589. 

The modification of porphyrins leading to isobacteriochlorins by C —C-bond formation is important to obtain a wide range of structurally different isobacteriochlorins which can then be further transformed. Protoporphyrin, deutoroporphyrin and hematoporphyrin (readily accessible from red blood pigment) are interesting and useful starting materials in the synthesis of isobacteriochlorins. 

R. O. Duthaler, A. Hafner, M. Riediker in Asymmetric C-C Bond Formation with Ti-, Zr-, and Hf-Carbohydrate Complexes in Organic Synthesis via Organometallics, K. H. Dotz, R.W Hoffmann, Eds., pp 285-310, Vieweg, Braunschweig 1990. 

Many other known pyruvate lyases are unsuited to application in asymmetric synthesis since they catalyze C-C bond formation with random stereochemistry30. 

The use of (TMSlsSiH with acyl selenides can also yield new C-C bond formation, as shown with the a,/l-unsaturated lactam ester (Reaction 67). The resulting ketone can be envisaged as potentially useful for the synthesis of 2-acylindole alkaloids. Both the effects of H-donating ability and steric hindrance by the silicon hydride are evident. 

Abstract Many similarities between the chemistry of carbon and phosphorus in low coordination numbers (i.e.,CN=l or 2) have been established. In particular, the parallel between the molecular chemistry of the P=C bond in phosphaalkenes and the C=C bond in olefins has attracted considerable attention. An emerging area in this field involves expanding the analogy between P=C and C=C bonds to polymer science. This review provides a background to this new area by describing the relevant synthetic methods for P=C bond formation and known phosphorus-carbon analogies in molecular chemistry. Recent advances in the addition polymerization of phosphaalkenes and the synthesis and properties of Tx-con-jugated poly(p-phenylenephosphaalkene)s will be described. 

Scheme 15 Iron(III)-mediated synthesis of alkenyl halides via direct C-C bond formation of benzylic alcohols and aryl alkynes...

Carbocations are highly reactive species that can be used for C-C bond formation. One driver for using continuous micro chemical processing is to employ also unstable cations, which are not amenable to batch synthesis because they decompose before they can actually be used [66, 67]. 

As C-C bond formation is an important step in organic synthesis, particularly for pharmaceutical applications, it is useful to look for operation modes of chemical micro processing that allow one to carry out combinatorial chemistry investigations. As such, the serial introduction of multiple reactant streams by flow switching was identified [66,67]. The wide availability of precursors for acyiiminium cations has led to the expression cation pool [66, 67]. 

Oiganic synthesis 30 [OS 30] Electrooxidative C-C bond formation of carbamates... 

Chiral sulphoxides are the most important group of compounds among a vast number of various types of chiral organosulphur compounds. In the first period of the development of sulphur stereochemistry, optically active sulphoxides were mainly used as model compounds in stereochemical studies . At present, chiral sulphoxides play an important role in asymmetric synthesis, esp>ecially in an asymmetric C—C bond formation . Therefore, much effort has been devoted to elaboration of convenient methods for their synthesis. Until now, optically active sulphoxides have been obtained in the following ways optical resolution, asymmetric synthesis, kinetic resolution and stereospecific synthesis. These methods are briefly discussed below. 

Since the seminal contributions by Nugent and RajanBabu the field of reductive C - C bond formation after epoxide opening via electron transfer has developed at a rapid pace. Novel catalytic methodology, enantio- and stereoselective synthesis and numerous applications in the preparation of biologically active substances and natural products have evolved. In brief, a large repertoire of useful and original reactions is available. These reactions are waiting to be applied in a complex context ... 

A common procedure in C-C-bond formation is the aldol addition of enolates derived from carboxylic acid derivatives with aldehydes to provide the anion of the [5-hydroxy carboxylic acid derivative. If one starts with an activated acid derivative, the formation of a [Mac lone can follow. This procedure has been used by the group of Taylor [137] for the first synthesis of the l-oxo-2-oxa-5-azaspiro[3.4]octane framework. Schick and coworkers have utilized the method for their assembly of key intermediates for the preparation of enzyme inhibitors of the tetrahydrolipstatin and tetrahydroesterastin type [138]. Romo and coworkers used a Mukaiyama aldol/lac-tonization sequence as a concise and direct route to 3-lactones of type 2-253, starting from different aldehydes 2-251 and readily available thiopyridylsilylketenes 2-252 (Scheme 2.60) [139]. 

From the foregoing it can be seen that the nitro group can be activated for C C bond formation in various ways. Classically the nitro group facilitates the Henry reaction, Michael addition, and Diels-Alder reaction. Kornblum and Russell have introduced a new substitution reaction, which proceeds via a one electron-transfer process (SrnI). The SrnI reactions have recently been recognized as useful tools in organic synthesis. All these reactions can be used for the preparation of alkenes as described in this chapter. 

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