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New Methods for Functional Group Conversion

2011· book-chapter· en· W3101741520 on OpenAlexaboutno aff
Douglass Taber

Bibliographic record

VenueOxford University Press eBooks · 2011
Typebook-chapter
Languageen
FieldChemistry
TopicAsymmetric Hydrogenation and Catalysis
Canadian institutionsnot available
Fundersnot available
KeywordsReductive aminationChemistryAmideAqueous solutionAminationCatalysisAmine gas treatingOrganic chemistryMedicinal chemistryCombinatorial chemistry

Abstract

fetched live from OpenAlex

Yujiro Hayashi of Tokyo University of Science and Teruaki Mukaiyama of the Kitasato Institute developed (Chem. Lett. 2008, 37, 592) a reduction-oxidation method for converting primary, secondary (such as 1, with clean inversion) and tertiary alcohols to sulfides. Peter A. Crooks of the University of Kentucky found (Chem. Lett. 2008, 37, 528) that tetrabenzylpyrophosphate 5 was an effective agent for condensing an acid 4 with an amine 6 to give the amide 7. This protocol, that runs in near quantitative yield in an hour at room temperature, with all impurities readily removable by washing with aqueous base and aqueous acid, appears to be well-suited both for scale-up, and for solid-phase synthesis. Balchandra M. Bhanage of the University of Mumbai reported (Tetrahedron Lett. 2008, 49, 965) the reductive amination of aldehydes, including 8, and ketones to the corresponding amines, using H2 and an inexpensive Fe catalyst. André Charette of the Université de Montréal showed (J. Am. Chem. Soc. 2008, 130, 18) that the Hantzsch ester 12 , in the presence of Tf2O, reduced amides selectively to amines. Esters, epoxides, ketones, nitriles and alkynes were stable to these conditions. Matthew Tudge of Merck Rahway demonstrated (Tetrahedron Lett . 2008, 49, 1041) that Br2 in DME activated NaBH4 , allowing facile reduction of esters, including the congested diester 14, at ambient temperature. David J. Procter of the University of Manchester made (J. Am. Chem. Soc. 2008, 130, 1136) the remarkable observation that six-membered ring lactones such as 16 were reduced to the corresponding diol with SmI2 . Five-membered ring and seven-membered ring lactones were not reduced under these conditions. Bruce H. Lipshutz of the University of California, Santa Barbara devised (Organic Lett . 2008, 10, 289) a convenient and economical procedure for CuH, using Cu and an inexpensive ligand in catalytic amounts, with PMHS as the bulk reductant. The reduction of 18 presumably proceeds by electron transfer, as with dissolving metal reduction, delivering 19 with the more stable trans ring fusion. In the presence of t-BuOH as a proton source, the reduction goes on to the alcohol 20.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.014
Threshold uncertainty score0.046

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0000.001
Bibliometrics0.0010.001
Science and technology studies0.0010.001
Scholarly communication0.0010.002
Open science0.0010.001
Research integrity0.0010.004
Insufficient payload (model declined to judge)0.0140.006

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.042
GPT teacher head0.242
Teacher spread0.200 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designNot applicable
Domainnot available
GenreMethods

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2011
Admission routes1
Has abstractyes

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