Cyclic oxonium derivatives of cobalt and iron bis(dicarbollides) and their use in organic synthesis

Abstract

The rapid progress in the chemistry of carboranes and other polyhedral boron compounds makes the development of methods for the synthesis of their various functional derivatives a high priority. The formation of cyclic oxonium derivatives followed by the ring opening is one of the most efficient methods for the preparation of these compounds. This review addresses the data on the use of the nucleophilic ring opening of cyclic oxonium derivatives based on cobalt and iron bis(dicarbollides), which have been extensively studied in recent years. Reactions involving O-, N-, S-, P- and C-nucleophiles are considered as a route to the targeted synthesis of a wide range of organic boron derivatives, in particular various boron-containing biologically active compounds. Possible applications of the reaction products are discussed. The bibliography includes 197 references.

New Azido Coumarins as Potential Agents for Fluorescent Labeling and Their “Click” Chemistry Reactions for the Conjugation with closo-Dodecaborate Anion

“…An effective approach to the functionalization of the closo -dodecaborate anion is the opening of its cyclic oxonium derivatives by nucleophiles [ 76 ]. This approach is widely used for the synthesis of its various functional derivatives and attachment to biomolecules [ 64 , 77 , 78 ], and has also been used to modify other polyhedral boron hydrides such as the closo -decaborate anion [ 64 ], nido -carborane [ 79 ], and cobalt and iron bis(dicarbollides) [ 80 ]. In particular, the synthesis of the earlier described coumarin derivatives of the closo -dodecaborate anion is based on the opening of oxonium rings with hydroxy groups at various positions of the coumarin heterocycle [ 72 , 73 , 74 ].…”

Synthesis of Cobalt Bis(Dicarbollide)—Curcumin Conjugates for Potential Use in Boron Neutron Capture Therapy

“…One of the common methods used for the functionalization of polyhedral boron hydrides and their binding to different biomolecules is based on the nucleophilic ring opening of cyclic oxonium derivatives. The oxonium derivatives of cobalt bis(dicarbollide) react with alcohols to give corresponding substituted derivatives of cobalt bis(dicarbollide) [ 40 ]. In this study, we used cobalt bis(dicarbollide) derivatives with different oxonium cycles 1 and 2 and curcumin 3 .…”

Synthesis and Reactivity of Cyclic Oxonium Derivatives of nido-Carborane: A Review

“…The use of ring opening reactions of cyclic oxonium derivatives of polyhedral boron hydrides under the action of nucleophiles for the preparation of their various derivatives is well known [56][57][58]. In the case of nido-carborane, this method has several advantages.…”

“…Several approaches to the synthesis of symmetrically substituted derivatives of nidocarborane [10-X-7,8-C 2 B 9 H 11 ] − with boron-sulfur [50,51] and boron-nitrogen [52][53][54][55] bonds have also been developed recently; however, the greatest interest is the functionalization of nido-carborane via its cyclic oxonium derivatives. Previously, this approach was successfully used for the synthesis of numerous derivatives of closo-decaborate and closo-dodecaborate anions [56,57], as well as sandwich bis(dicarbollide) transition metal complexes [58]. In this contribution synthesis and properties of cyclic oxonium derivatives of nido-carborane as well as half-sandwich complexes based on it will be reviewed.…”