buchner ring造句

• In the Buchner ring expansion diazo compounds react with aromatic rings with ring-expansion.
• The Simmons-Smith reaction adds to alkenes while the Buchner ring expansion allows addition to typically unreactive arenes.
• The Buchner ring expansion method has been used to synthesize starting materials for applications in material science involving photovoltaic cells.
• The Buchner ring expansion is encouraged to open to the desired product by placing electron withdrawing groups on the carbon added.
• The reaction mechanism of a Buchner ring expansion begins with carbene formation from ethyl-diazoacetate generated initially through photochemical or thermal reactions with extrusion of nitrogen.
• While studying an analogous reaction of carbene addition to thiophene, Stephen Matlin and Lam Chan applied the Buchner ring expansion method in 1981 to generate spiro derivatives of Penicillin.
• The Buchner ring expansion reaction was first used in 1885 by E . Buchner and T . Curtius who prepared a carbene from ethyl diazoacetate for addition to benzene using both thermal and photochemical pathways in the synthesis of cycloheptatriene derivatives.
• The Buchner ring expansion is useful because it gives cycloheptatrienes as the ring opened products, which are found in the core of some natural products, such as azulenes . An important consideration in these ring expansions is the ring opening to an expanded ring and not an exocyclic group on the original ring or an unopenable product.
• Other methods exist to cyclopropantate other functionalities, such as the Buchner ring expansion fornucleophihlic attack ( A ) and neighboring group donation ( B ) . The formation of the cyclopropane ring in a single carbon expansion allows the introduction of additional functionality along with the ring expansion, provided the additional functionality is appended to the carbon being inserted.