Spiroborate catalyzed reductions with N,N-diethylaniline borane

Coleridge, Brian M.; Angert, Thomas P.; Marks, Lucas R.; Hamilton, Patrick N.; Sutton, Christopher P.; Matos, Karl; Burkhardt, Elizabeth R.

doi:10.1016/j.tetlet.2010.09.022

Cited by 7 publications

(4 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The conversion of 59 to oxazine 60 was envisioned to be difficult given the potential for facile reductive cleavage of the N−O bond . After screening various known methods for the reduction of hydroxamic esters to O ‐alkyl hydroxylamines, conditions adapted from Reinhoudt and co‐workers, employing monochloroalane as the reductant, proved most effective and simultaneously removed the cyclic carbonate thereby producing the oxazabicyclo[3.3.1]nonane core of 1 in 63 % yield. Subsequent oxidation of 60 with DMP gave relatively unstable enone 61 , which was taken directly to the next step to minimize decomposition.…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of (±)‐Phyllantidine: Development and Mechanistic Evaluation of a Ring Expansion for Installation of Embedded Nitrogen‐Oxygen Bonds

et al. 2020

View full text Add to dashboard Cite

The development of a concise total synthesis of (±)‐phyllantidine (1), a member of the securinega family of alkaloids containing an unusual oxazabicyclo[3.3.1]nonane core, is described. The synthesis employs a unique synthetic strategy featuring the ring expansion of a substituted cyclopentanone to a cyclic hydroxamic acid as a key step that allows facile installation of the embedded nitrogen‐oxygen (N−O) bond. The optimization of this sequence to effect the desired regiochemical outcome and its mechanistic underpinnings were assessed both computationally and experimentally. This synthetic approach also features an early‐stage diastereoselective aldol reaction to assemble the substituted cyclopentanone, a mild reduction of an amide intermediate without N−O bond cleavage, and the rapid assembly of the butenolide found in (1) via use of the Bestmann ylide.

show abstract

Section: Resultsmentioning

confidence: 99%

Total Synthesis of (±)‐Phyllantidine: Development and Mechanistic Evaluation of a Ring Expansion for Installation of Embedded Nitrogen‐Oxygen Bonds

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Although they are air- and moisture-stable and safe to handle in open-air environments, their strong complexation with amines renders the borane–amines less reactive. The weak coordination between boron and nitrogen in bulky trialkylamine–boranes was exploited for representative tert-amide reduction using N , N -diethylaniline borane [ 29 , 30 ]. The reduction of tert-carboxamides and lactams using aminoborohydrides [ 28 , 31 ], as well as sec- and tert-amides using aminodiborane [ 32 ], both generated from borane–amines, have also been reported.…”

Section: Introductionmentioning

confidence: 99%

“…Molecules 2023, 28, x FOR PEER REVIEW 2 of 12 trialkylamine-boranes was exploited for representative tert-amide reduction using N,Ndiethylaniline borane [29,30]. The reduction of tert-carboxamides and lactams using aminoborohydrides [28,31], as well as sec-and tert-amides using aminodiborane [32], both generated from borane-amines, have also been reported.…”

Section: Introductionmentioning

confidence: 99%

“…We envisioned that the use of borane-ammonia would release only ammonia and provide pure product amines. On the basis of the reported reduction of amides using 2 equivalents of borane derivatives, such as BTHF and BMS [18,19], we aimed to achieve the reduction, if possible, using ≤2.0 equivalents of trialkylamine-boranes was exploited for representative tert-amide reduction using N,Ndiethylaniline borane [29,30]. The reduction of tert-carboxamides and lactams using aminoborohydrides [28,31], as well as sec-and tert-amides using aminodiborane [32], both generated from borane-amines, have also been reported.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Titanium-Mediated Reduction of Carboxamides to Amines with Borane–Ammonia

2023

View full text Add to dashboard Cite

In this study, the successful titanium tetrachloride-catalyzed reduction of aldehydes, ketones, carboxylic acids, and nitriles with borane–ammonia was extended to the reduction (deoxygenation) of a variety of aromatic and aliphatic pri-, sec- and tert-carboxamides, by changing the stoichiometry of the catalyst and reductant. The corresponding amines were isolated in good to excellent yields, following a simple acid–base workup.

show abstract

Total Synthesis of (±)‐Phyllantidine: Development and Mechanistic Evaluation of a Ring Expansion for Installation of Embedded Nitrogen‐Oxygen Bonds

et al. 2020

View full text Add to dashboard Cite

The development of aconcise total synthesis of (AE)phyllantidine (1), am ember of the securinega family of alkaloids containing an unusual oxazabicyclo[3.3.1]nonane core,i sd escribed. The synthesis employs au nique synthetic strategy featuring the ring expansion of as ubstituted cyclopentanone to acyclic hydroxamic acid as akey step that allows facile installation of the embedded nitrogen-oxygen (NÀO) bond. The optimization of this sequence to effect the desired regiochemical outcome and its mechanistic underpinnings were assessed both computationally and experimentally.T his synthetic approach also features an early-stage diastereoselective aldol reaction to assemble the substituted cyclopentanone, amild reduction of an amide intermediate without NÀObond cleavage,and the rapid assembly of the butenolide found in (1) via use of the Bestmann ylide. AngewandteChemie Forschungsartikel Scheme 10. Deprotection of TBS ether in aldol adduct 18. Scheme 11. Ring expansion of acetonide-protected acyloxy nitroso 43. Scheme 12. Preparation of carbonate-protected acyloxy nitroso adduct 48.

show abstract

Spiroborate catalyzed reductions with N,N-diethylaniline borane

Cited by 7 publications

References 32 publications

Total Synthesis of (±)‐Phyllantidine: Development and Mechanistic Evaluation of a Ring Expansion for Installation of Embedded Nitrogen‐Oxygen Bonds

Total Synthesis of (±)‐Phyllantidine: Development and Mechanistic Evaluation of a Ring Expansion for Installation of Embedded Nitrogen‐Oxygen Bonds

Titanium-Mediated Reduction of Carboxamides to Amines with Borane–Ammonia

Total Synthesis of (±)‐Phyllantidine: Development and Mechanistic Evaluation of a Ring Expansion for Installation of Embedded Nitrogen‐Oxygen Bonds

Contact Info

Product

Resources

About