Controlled Reduction of Carboxamides to Alcohols or Amines by Zinc Hydrides

Abstract

ZuschriftenScheme 2. Substrate scope.[a] The reactions were conducted using 0.5 mmol of the amides 1.Y ields of the isolated alcohols 2 and amines 3 are given.[b] The reaction was conducted using 5equiv of NaH, 2equiv of ZnI 2 and 2equiv of NaI.[c] The reaction was conducted using 7equiv of NaH and 3.5 equiv of ZnCl 2 .[d] 1aj > 98 %ee; 2aj > 97 %ee; 3aj > 98 % ee as measured by the Mosher method (see the Supporting Information).[e] Amine 3ak was formed in 35 %yield. [f]Amine 3al was formed in 31 %yield. Bn = benzyl, Ph = phenyl, TIPS = triisopropylsilyl.Scheme 5. DFT calculations for model reactions of benzamide with (ZnH 2 ) 2 or (ZnHCl) 2 species. Energy changes and bond lengths at the wB97XD/SDD&6-31 + G* (scrf = smd, THF) level of theory are shown in kcal mol À1 and ,respectively.

Palladium doping of In2O3 towards a general and selective catalytic hydrogenation of amides to amines and alcohols

“…4 Traditionally, amide reduction reactions have been carried out using (over)stoichiometric amounts of classical reagents such as lithium aluminum hydride (LiAlH 4 ) or boranes (B 2 H 6 ), which require tedious workup procedures and generate large amounts of waste. 5 Recently emerged non-catalytic protocols using samarium iodide (SmI 2 )/amine/H 2 O, 6 sodium dispersions with different proton donors, 7 or sodium hydride (NaH) with zinc halides (ZnX 2 ; X = Cl, I) 8 have similar limitations. Different catalytic strategies have been developed for the reduction of amides to amines under hydrosilylation, 9 hydroboration 10 and transfer-hydrogenation 11 conditions, which are methodologies with wide applicability for functionalized amides, but they suffer from low atom-efficiency.…”

Synthetic Organic Reactions Mediated by Sodium Hydride

“…Our current interest is use of NaH as a potent hydride source for generation of other main group metal hydrides through readily available main group metal halides. 40,41 It is our strong belief that the leveraging of main group metal hydrides to exploit new molecular transformations continues to ourish and thus enhance our synthetic capability.…”

Benchmarking DFT Calculations of 1H and 13C Chemical Shifts in Monosubstituted Ferrocenes

“…The experimental chemical shifts were obtained from the literature: ferrocene ( a ), [ 98–99 ] methylferrocene ( b ), [ 100 ] ethylferrocene ( c ), [ 101 ] phenylferrocene ( d ), [ 102–103 ] 4‐iodophenylferrocene ( e ), [ 104 ] ethynylferrocene ( f ), [ 105 ] ferrocenylmethanol ( g ), [ 106 ] 1‐ferrocenylethanol ( h ), [ 107 ] N , N ‐dimethylaminomethylferrocene ( i ), [ 108 ] formylferrocene ( j ), [ 108 ] ferrocenecarboxylic acid ( k ), [ 109 ] acetylferrocene ( l ), [ 108 ] N , N ‐dimethylferroceneamide ( m ), [ 106 ] fluoroferrocene ( n ), [ 110–111 ] chloroferrocene ( o ), [ 112 ] bromoferrocene ( p ), [ 112 ] trimethylferrocenylphosphonium hexafluorophosphate ( q ), [ 113 ] iodoferrocene ( r ), [ 112 ] cyanoferrocene ( s ), [ 114 ] ferroceneboronic acid ( t ), [ 115 ] 1,1′‐dimethylferrocene, [ 116–117 ] 1,1′‐diphenylferrocene, [ 118 ] 1,1′‐ferrocenediboronic acid, [ 118 ] 1,1′‐ferrocenedicarboxylic acid, [ 119–120 ] 1,1′‐diacetylferrocene, [ 120–121 ] 1′‐trimethylsilylethynyl‐1‐ethynylferrocene, [ 122 ] 1′‐bromo‐1‐ferrocenylcarboxylic acid, [ 123 ] and decamethylferrocene. [ 124 ] The extracted data are given in Tables S10 and S14.…”