Planar chiral (η5-cyclohexadienyl)- and (η6-arene)-tricarbonylmanganese complexes: synthetic routes and application

Abstract

Planar chiral arenetricarbonylchromium complexes have been intensively investigated and they have been applied as valuable building blocks for asymmetric synthesis and as ligands for asymmetric catalysis. In contrast, in the field of the isoelectronic cationic [(η(6)-arene)Mn(CO)(3)](+) complexes, until these last 10 years, very few studies were published involving nonracemic planar chiral cationic complexes and their potential applications, certainly because of the difficult access to enantiopure starting material. In 2009, however, the discovery of the first resolution of such compounds opened a new area for their application in the field of organic as well as of organometallic enantioselective syntheses. We felt it important to write a review on this subject to give an up-to-date summary of the methodologies used to prepare enantiomerically pure planar chiral neutral [(η(5)-cyclohexadienyl)Mn(CO)(3)] and cationic [(η(6)-arene)Mn(CO)(3)](+) complexes as well as their potential in enantioselective synthesis.

Tetrathia[7]helicene-Based Complexes of Ferrocene and (η5-Cyclohexadienyl)tricarbonylmanganese: Synthesis and Electrochemical Studies

“…In the course of studies concerning the structure and the reactivity of neutral (η 6 -arene)Cr(CO) 3 , cationic (η 6 -arene)Mn(CO) 3 , and cationic (η 6 -arene)Fe(C 5 H 5 ) derivatives it has been reported that a nucleophile can easily add to the coordinated arene ring, affording (η 5 -cyclohexadienyl)[M] ([M] = Cr(CO) 3 – , Mn(CO) 3 , Fe(C 5 H 5 )) complexes. In the case of the Mn series, these η 5 complexes are very stable and easily functionalizable either by a lithiation/electrophilic quench sequence or by palladium cross-coupling reactions .…”

Isocyanurates with Planar Chirality: Design, Optical Resolution, and Isomerization

“…1C). [10][11][12][13][14][20][21][22][23][24][25][26][27][28][29][30][31] Bridging between P and Q with two flexible linkers (L 1 s) generates cyclic molecules such as cyclophanes [1][2][3][4][5][6][7][8][9][15][16][17][18][19] and strapped porphyrins, [50][51][52][53][54][55][56] which is also one of the most widely used strategy (Fig. 1D).…”

“…Planar‐chiral molecules have been developed from the aspect of not only unique three‐dimensional structures but also potential applications to auxiliaries and catalysts for asymmetric syntheses, catalysts for stereospecific polymerizations, and chiral sensors . Our previous interests were focused on chiral porphyrins having topological chiralities to provide model compounds of chiral porphinoids being abundant in living systems .…”

“…Metal (Q)‐coordination perpendicular to the enantiotopic plane of P is one of the most widely used strategy; chiral metallocenes and π‐arene complexes are representatives (Fig. C) . Bridging between P and Q with two flexible linkers (L 1 s) generates cyclic molecules such as cyclophanes and strapped porphyrins, which is also one of the most widely used strategy (Fig.…”

Ferrocenyl-Substituted (η5-Hydroxyalkylcyclohexadienyl)tricarbonylmanganese Complexes: Synthesis, Structural Determinations, and Formation of Carbenium Ions

“…The reactivity of an arene ring is dramatically modified by coordination to a metal tricarbonyl tripod such as Cr(CO) 3 or Mn(CO) 3 , allowing a variety of transformations which are impossible to achieve on a free arene . The reactivity is altered of not only ring carbons but also that of groups in benzylic positions.…”