ChemInform Abstract: Dehydrative Fragmentation of 5‐Hydroxyalkyl‐1H‐tetrazoles: A Mild Route to Alkylidenecarbenes.

Abstract

The tetrazoles are prepared via an optimized literature procedure starting from aldehydes, ketones or ynones.

Acceleration of 1,3-Dipolar Cycloadditions by Integration of Strain and Electronic Tuning

“…Dehydration with EDC in THF gave a tetraazafulvene intermediate, which expelled dinitrogen to generate an unstable alkylidene carbene. 62 Its [1,2]-rearrangement 63 afforded the desired cyclooctyne. Adventitiously, this opportunistic route to ABC affords a chloro group that is an ideal handle for functionalization through well-established aryl chloride coupling chem- istry.…”

N-Morpholinomethyl-5-lithiotetrazole: A Reagent for the One-Pot Synthesis of 5-(1-Hydroxyalkyl)tetrazoles

“…The reaction mixture was then concentrated under reduced pressure to provide a residue, which was 2969,2954,2923,2904,2869,2846,1478,1456,1435,1422,1398,1386,1366,1327,1319,1295,1264,1240,1217,1167,1147,1110,1101,1071,1035,1008,963,897,859,853,775,753,717,672,652 Method A: Preformation of Tetrazole Anion. Diphenyl(1Htetrazol-5-yl)methanol (16a): 11 To a stirred solution of 4-((Ntetrazolyl)methyl)morpholine ( 13) (326 mg, 2 mmol, 2 equiv) in THF (4.0 mL), under nitrogen at −78 °C (acetone/CO 2 ), was added to a freshly prepared solution of LHMDS (351 mg, 2.1 mmol, 2.1 equiv) in THF (2.0 mL), dropwise via syringe. After the mixture was stirred for 30 min at −78 °C, a solution of benzophenone (15a) (182 mg, 1 mmol, 1.0 equiv) in THF (2.0 mL) was added dropwise.…”

“…Diphenyl(1Htetrazol-5-yl)methanol (16a). 11 To a stirred solution of 4-((Ntetrazolyl)methyl)morpholine ( 13) (338 mg, 2 mmol, 2 equiv) and benzophenone (15a) (182 mg, 1 mmol, 1 equiv) in THF (5.0 mL), under nitrogen at −78 °C (acetone/CO 2 ), was added a freshly prepared solution of LHMDS (351 mg, 2.1 mmol, 2.1 equiv) in THF (2.0 mL) dropwise via syringe over 5 min. The reaction was stirred for 2 h at −78 °C, allowed to warm to room temperature over 14 h, and then concentrated under reduced pressure.…”

Functionalization of 1N-Protected Tetrazoles by Deprotonation with the Turbo Grignard Reagent

“…14,15 In addition, 5-(1-hydroxyalkyl)tetrazoles have been demonstrated as precursors of alkylidenecarbenes, which undergo rearrangements to acetylenes or C−H insertion reactions. 16,17 The synthesis of tetrazole derivatives 3 involves two general approaches: construction of the cycle via cycloaddition or electrocyclization reactions 18,19 and the modification of Nprotected tetrazole at the fifth position (Scheme 1). 16,20−24 The latter can be done via C−H deprotonation of tetrazole 1 or halogen-metal exchange of halogen derivative 2 to generate organometallic intermediates that are subjected to further modifications.…”