Norbornane framework

The Leuckart-Wallach reaction is the oldest method of reductive amination of carbonyl compounds. It makes use of formamide, formic acid or ammonium formate at high temperature. The final product is a formamide derivative, which can be converted to an amine by reduction or hydrolysis. The method has been applied to the preparation of 1,2-diamines with a norbornane framework, which are interesting rigid analogues of 1,2-diaminocyclohexanes. As a matter of fact, starting from N-acetyl-2-oxo-l-norbornylamine 222, the diamide 223 was obtained with excellent diastereoselectivity and then converted to the M-methyl-N -ethyl derivative 224 by reduction with borane [ 104] (Scheme 34). On the other hand, when the reac-... 

While f -amino alcohols have been widely studied as chiral auxiliaries, a series of (S)-amino alcohols - built into norbornane frameworks - have been examined as catalysts of enantioselective addition of dialkylzincs to benzaldehydes.236... 

Cp(CO)2Cr]5P10 (204) is based on a norbornane framework with additional P and P2 units attached, whereas in [(CpM4E)Rh]4Pi0 (205) it is structurally related to dihydrofulvalene. The norbornane structure also appears in [Ni P Bu3 2]4P14 (206), where two P7 units are connected. 

An efficient protocol for the synthesis of syn-facially bridged norbornane frameworks has been developed via the tandem cyclization-cycloaddition reactions of the carbonyl ylide 57 with norbornene derivatives. The reaction of the diazo ketone 56 with the dipolarophile 62 in the presence of Rh2(OAc)4 furnished [85] the 5y -facially bridged oxa-norbornane framework 63 in high yield (Scheme 17). 

Stereoselectivity is also induced by the zeolite framework surrounding the active site in the oxidation of norbornane and methyl cyclohexane by PhIO [49-50,63-64]. The zeolite orientates the incoming substrate in such a way that one of the two diastereotopic C-H bonds has a greater chance to be oxidized. 

The Hantzsch-Widman system is well suited for the naming of saturated monocyclic compounds. Bridged ring systems, however, present a special challenge, and here the replacement system is preferred. An example is provided by the framework of the bicyclic hydrocarbon norbornane. Heteroatoms may in principle be substituted for any of the carbons. To illustrate, nitrogen substitution at position 7 would give rise to the name 7-azanorbomane. 

Common bicycloalkanes such as norbornane may be classed as outside-outside bicyclics since their bridgehead hydrogen atoms both lie outside the carbon skeleton. The Diels-Alder reaction between hexafluorobut-2-yne and c ,tra/t -cyclododeca-l,3-diene has been used to synthesize an example of a novel class of inside-outside carbobicyclic dienes, namely (158), in which one bridgehead hydrogen atom lies inside, and one outside, the carbo-cyclic framework. This type of structural isomerism is termed atropism. ... 

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