Synthesis and structure of an air-stable hypervalent organobismuth (III) perfluorooctanesulfonate and its use as high-efficiency catalyst for Mannich-type reactions in water

Synthesis and structure of an air-stable organoantimony complex and its use as a catalyst for direct diastereoselective Mannich reactions in water

“…To demonstrate the superiority of complex 1, its catalytic performance is compared with that of precursor C 6 H 11 N(C 6 H 4 CH 2 ) 2 SbCl 2, cationic organobismuth [S(CH 2 C 6 H 4 ) 2 Bi(OH 2 )] + [ClO 4 ] À 3 [15], and antimony trichloride 4 [45]. As shown in Table 4, catalyst 1 is superior to the others in efficiency as well as in diastereoselectivity.…”

“…Recently, we reported a cationic organobismuth perchlorate complex ([S(CH 2 C 6 H 4 ) 2 Bi(OH 2 )] + [ClO 4 ] À ) that is catalytically highly active, giving anti/syn molar ratio 6 95/5 in the direct diastereoselective Mannich reaction [14]. On the other hand, no diastereoselectivity was observed over covalent organobismuth(III) perfluorooctanesulfonate (C 6 H 11 N(CH 2 C 6 H 4 ) 2 Bi(OSO 2 C 8 F 17 )) although its catalytic efficiency towards the Mannich-type reactions was high [15].…”

Hf(OTf)4 as a Highly Potent Catalyst for the Synthesis of Mannich Bases under Solvent-Free Conditions

“…Meanwhile, various metal Lewis acids, such as Yb(OPf) 3 [16], ZrOCl 2 ·8H 2 O [17], Zn(OTf) 2 [18], NbCl 5 [19], SnCl 2 /SnCl 4 [20,21], BiCl 3 [22], CeCl 3 ·7H 2 O/CAN [23,24], FeCp 2 PF 6 [25], and Ga(OTf) 3 [26] have been employed for the synthesis of Mannich bases under either solution-phase or solvent-free conditions. In addition, organometallic complexes of Ti(IV) [27], Bi(III) [28], Sb(III) [29], Zr(IV) [30,31], along with other Lewis acids, such as sulfonium [32]/iodonium salts [33] and SiCl 4 [34], have also been proved as effective catalysts for this purpose. However, these methods typically require at least 5-10 mol% catalyst.…”

Synthesis, Structure and Applications of Hypervalent Organoantimony Compounds Having Intramolecular E→Sb (E = N, O, S) Coordinations

“…However, the utilization of organoantimony(III) compounds as Lewis acid catalysts for organic synthesis was rarely reported partly due to the unstable nature of organoantimony compounds. Recently, Yin and co-workers reported a series of air-stable organobismuth(III) with cyclic 5,6,7,12-tetrahydrodibenz[c,f] [1,5] heterobismocine framework that are catalytically active toward many organic reactions in aqueous media as well as in various organic solvents [67,[101][102][103][104][105]. In order to develop suitable organoantimony compounds for catalytic utilization, Yin and co-workers synthesized organoantimony with analogous tetrahydrodibenzo[c,f] [1,5]azastibocine framework, and found that organoantimony(III) triflate (50) can efficiently catalyze the direct diastereoselective Mannich reaction in water (Scheme 46), giving anti/syn molar ratio 95/5 [64].…”