Unique Stereocontrol in Carborane Chemistry: Skeletal Alkylcarbonation (SAC) versus Exoskeletal Alkylmethylation (EAM) Reactions

0443607 - ÚACH 2016 RIV DE eng J - Článek v odborném periodiku
Bakardjiev, Mario - Holub, Josef - Macháček, Jan - Hnyk, Drahomír - Štíbr, Bohumil - Růžičková, Z. - Růžička, A.
Unique Stereocontrol in Carborane Chemistry: Skeletal Alkylcarbonation (SAC) versus Exoskeletal Alkylmethylation (EAM) Reactions.
Angewandte Chemie - International Edition. Roč. 54, č. 16 (2015), s. 4937-4940. ISSN 1433-7851. E-ISSN 1521-3773
Grant CEP: GA ČR(CZ) GAP207/11/0705
Institucionální podpora: RVO:61388980
Klíčová slova: NMR spectroscopy * carboranes * dicarbaboranes * stereocontrol * tricarbaboranes
Kód oboru RIV: CA - Anorganická chemie
Impakt faktor: 11.709, rok: 2015

Reactions between the arachno-6,9-C2 B8 H14 (1) dicarbaborane and acyl chlorides, RCOCl (2), are subject to stereocontrol that completely changes the nature of the reaction products. While most chlorides produce the 8-R-nido-7,8,9-C3 B8 H11 (3) tricarbollides (by skeletal alkylcarbonation=SAC), bulky RCOCls (2; where R=1-adamantyl, 2a; 1-mesityl, 2b; 9-anthranyl, 2c; 1-naphthyl, 2d) in 1,2-dichloroethane (DCE) in the presence of triethylamine at 40-60°C gave a series of entirely different 1-R-2-CH3 -closo-1,6-C2 B8 H8 (4) dicarbaboranes upon acidification with conc. H2 SO4 (by exosleletal alkylmehylation=EAM). Both types of reactions seem to proceed via a common [8-R-nido-7,8,9-C3 B8 H10 ](-) (3(-) ) anion which in the EAM case is unstable because of steric crowd and undergoes rearrangement via the isomeric [R-nido-7,8,10-C3 B8 H10 ](-) tricarbollide structures which, on protonation, undergo reductive extraction of one CH vertex to generate the 2-CH3 substituent in structure 4.
Trvalý link: http://hdl.handle.net/11104/0246299


Vědecká data: Wiley onlinelibrary