Cyclic halo ether compound

Cyclic halo ethers also undergo reaction with Grignard reagents. 3-Chloro-tetrahydro-2-propylpyran is formed in 73% yield from 2,3-dichlorotetrahydro-pyran and propylmagnesium bromide.345 In a reaction analogous to the Boord synthesis, compounds of this structure are readily cleaved by sodium to the unsaturated alkanols 345,346... 

Trimethylsilyl iodide (TMS—I), as such or generated in situ, is especially effective as a mild dehalogenation agent for halo ketones. The reaction appears to generate the enol silyl ether initially, and this is converted to the carbonyl compound during work-up (equation 12). Both cyclic and acyclic a-bromo and a-chloro ketones are dehalogenated, generally in excellent yields. Methyltrichlorosilane, on the other... 

Alkyl and 2-Alkenyl Halides or Sulfonates Ring Opening of Cyclic Amines and Ethers Addition onto Carbon-Carbon Multiple Bonds Addition onto Heteroconjugated Multiple Bonds Nucleophilic Substitution of 1-Alkenyl Halides Nucleophilic Addition onto Arenes and Hetarenes Substitution of Halo-, Alkoxy-, and Metalloarenes or -hetarenes Addition onto Nonaromatic Carbon-Nitrogen Multiple Bonds Addition onto Carbonyl Compounds... 

Gallagher et al. reported on various IV-heterocycle construction via cyclic sulfamides. Using this strategy, they synthesized enantiopure 1,4-benzoxazine 311, which was the precursor of the blockbuster antibiotic levolloxacin 312 (Scheme 40.67). Starting from Boc-protected amino alcohol 305, sulfamidate 306 was prepared using RuCU and NaI04. 306 was treated with halo phenol 308 followed by acidic hydrolysis to afford amino ether 310. The compound 310 underwent Pd-catalyzed C—N alkylative cyclization to produce benzoxazine 311, which was the potential precursor from which Levolloxacin 312 can be synthesized. 

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