A highly efficient Ti-catalyst for the deoxygenative reduction of esters under ambient conditions: experimental and mechanistic insights from DFT studies

被引:4
作者
Bhattacharjee, Jayeeta [1 ]
Rawal, Parveen [2 ]
Das, Suman [1 ]
Harinath, Adimulam [1 ]
Gupta, Puneet [2 ]
Panda, Tarun K. [1 ]
机构
[1] Indian Inst Technol Hyderabad, Dept Chem, Sangareddy 502285, Telangana, India
[2] Indian Inst Technol Roorkee, Computat Catalysis Ctr, Dept Chem, Roorkee 247667, Uttarakhand, India
关键词
RING-OPENING POLYMERIZATION; SELECTIVE HYDROBORATION; CARBOXYLIC ESTERS; METAL-COMPLEXES; CARBONYL; NITRILES; AMIDES; APPROXIMATION; HYDROSILATION; HYDROGENATION;
D O I
10.1039/d2dt00076h
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
In this paper, we report the synthesis of dianionic amidophosphineborane-supported titanium chloride [{Ph2P(BH3)N}(2)C6H4TiCl2] (1) and Ti-IV alkyl complex [{Ph2P(BH3)N}(2)C6H4Ti(CH2SiMe3)(2)] (2) using a salt metathesis reaction. Ti-IV complex 1 was obtained by the reaction of the bis-borane ligand [{Ph2P(BH3)N}(2)C6H4] and TiCl4 in toluene followed by the addition of 2 equivalents of [LiN(SiMe3)(2)] at ambient temperature. Ti-IV bis-alkyl complex 2 was isolated from the reaction of complex 1 with 2.5 equivalents of LiCH2SiMe3 in toluene. The solid-state structure of complex 1 is established by single-crystal X-ray diffraction analysis. Ti-IV bis-alkyl complex 2 has proved to be a competent catalyst in the deoxygenative reduction of aliphatic and aromatic esters with pinacolborane (HBpin) to afford corresponding boryl ethers at room temperature under solvent-free conditions. Catalyst 2 exhibits chemoselectivity toward ester functionalities over halides, heteroatoms, olefins, and amino functional groups. DFT studies demonstrate that the active form of catalyst 2 is capable of easily transferring its hydrides to ester substrates at room temperature. The studies further reveal that the rate-limiting step (RLS) in an ester-to-boryl ether conversion is the cleavage of the C-O bond of an ester. In brief, the titanium-catalysed ester-to-boryl ether conversions are found to be downhill processes having small activation barriers along all mechanistic steps.
引用
收藏
页码:5859 / 5867
页数:9
相关论文
共 59 条
[1]  
[Anonymous], 2013, MARCHS ADV ORGANIC C
[2]   La[N(SiMe3)2]3-Catalyzed Ester Reductions with Pinacolborane: Scope and Mechanism of Ester Cleavage [J].
Barger, Christopher J. ;
Motta, Alessandro ;
Weidner, Victoria L. ;
Lohr, Tracy L. ;
Marks, Tobin J. .
ACS CATALYSIS, 2019, 9 (10) :9015-9024
[3]   Magnesium amide catalyzed selective hydroboration of esters [J].
Barman, Milan Kr. ;
Baishya, Ashim ;
Nembenna, Sharanappa .
DALTON TRANSACTIONS, 2017, 46 (13) :4152-4156
[4]   DENSITY-FUNCTIONAL EXCHANGE-ENERGY APPROXIMATION WITH CORRECT ASYMPTOTIC-BEHAVIOR [J].
BECKE, AD .
PHYSICAL REVIEW A, 1988, 38 (06) :3098-3100
[5]   Hydrosilylation of Esters Catalyzed by Bisphosphine Manganese(I) Complex: Selective Transformation of Esters to Alcohols [J].
Behera, Rakesh R. ;
Ghosh, Rahul ;
Panda, Surajit ;
Khamari, Subrat ;
Bagh, Bidraha .
ORGANIC LETTERS, 2020, 22 (09) :3642-3648
[6]   Iron-Catalyzed Hydrosilylation of Esters [J].
Bezier, David ;
Venkanna, Gopaladasu T. ;
Castro, Luis C. Misal ;
Zheng, Jianxia ;
Roisnel, Thierry ;
Sortais, Jean-Baptiste ;
Darcel, Christophe .
ADVANCED SYNTHESIS & CATALYSIS, 2012, 354 (10) :1879-1884
[7]   Recent development of alkali metal complex promoted iso-selective ring-opening polymerization of rac-Lactide [J].
Bhattacharjee, Jayeeta ;
Sarkar, Alok ;
Panda, Tarun K. .
CURRENT OPINION IN GREEN AND SUSTAINABLE CHEMISTRY, 2021, 31
[8]   Alkali and Alkaline Earth Metal Complexes as Versatile Catalysts for Ring-Opening Polymerization of Cyclic Esters [J].
Bhattacharjee, Jayeeta ;
Sarkar, Alok ;
Panda, Tarun K. .
CHEMICAL RECORD, 2021, 21 (08) :1898-1911
[9]   Alkaline Earth Metal-Mediated Highly Iso-selective Ring-Opening Polymerization of rac-Lactide [J].
Bhattacharjee, Jayeeta ;
Harinath, Adimulam ;
Sarkar, Alok ;
Panda, Tarun K. .
CHEMISTRY-AN ASIAN JOURNAL, 2020, 15 (06) :860-866
[10]   Highly Chemoselective Hydroboration of Alkynes and Nitriles Catalyzed by Group 4 Metal Amidophosphine-Borane Complexes [J].
Bhattacharjee, Jayeeta ;
Adimulam, Harinath ;
Bano, Kulsum ;
Panda, Tarun K. .
ACS OMEGA, 2020, 5 (03) :1595-1606