Reaction of (trichloromethyl)carbinyl tosylates with Grignard reagents

Reeve, Wilkins; Brown, Robert; Steckel, Thomas F.

doi:10.1021/ja00747a053

Cited by 8 publications

(4 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Presumably, this isomerization was caused by a trace amount of bromine in the products. Alternatively, a similar isomerization was found to occur by photolysis at 254 nm for 1 h (Scheme ). − …”

Section: Synthesis Of Gem-dihalovinyl Systemsmentioning

confidence: 91%

“…Reactions of Grignard reagents with tosylates of aryl-, alkyl-, and alkynyl(trichloromethyl) carbinols provided an attractive synthetic route to the related dichloroolefins (Scheme ). The reaction occurs by a polar, ionic mechanism in which two • MgBr radicals serve as reducing agents to supply two electrons to the tosylate, which in this way is expelled as anion …”

Section: Synthesis Of Gem-dihalovinyl Systemsmentioning

confidence: 99%

“…The reaction occurs by a polar, ionic mechanism in which two radicals serve as reducing agents to supply two electrons to the tosylate, which in this way is expelled as anion. 78 Trichloromethyl carbinols (i-PrCH(OH)CCl 3 and EtOC-H 2 CH(OH)CCl 3 ) were converted into the corresponding gem-dichloroalkenes, i-PrCHdCCl 2 and EtOCH 2 CHdCCl 2 , in 70% and 50% yield, respectively, by treatment with 2.5 equiv of P(NMe 2 ) 3 and an excess of CCl 4 . 26 A procedure for the preparation of gem-dichloroalkenes 43 has been developed via formation of trichloromethyl and dichloromethyl silylethers 41 and 42, obtained by addition of LiCHCl 2 or LiCCl 3 to aldehydes or ketones, followed by treatment of the intermediates with MeSiCl 3 (Scheme 46).…”

Section: Synthesis Of 11-dichloro-1-alkenesmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

2011

View full text Add to dashboard Cite

Vinyl halides 24 and 25 were prepared from the tribromoromethyl carbinol 23, obtained in turn by reaction of benzo[b]thiophene-2-carboxaldehyde with the tribromomethane anion 43 generated in situ from 2,2,2-tribromoethanoic acid in DMSO (Scheme 24). 44 The intermediate 23 was treated with SOCl 2 or Et 2 NSF 3 to give the vinyl halides 24 (33% yield) or 25 (32% yield) through halogenation followed by dehydrobromination.2.1.3. Substitution Reactions. Although the most common source for gem-dibromoalkenes are carbonyl compounds, there are some examples in which alkene and alkyne derivatives have been used as starting materials. Reaction of longifolene 26 and camphene 29 with Hg(OAc) 2 /NaCl resulted in the isolation of vinylic dimercurichlorides 27 and 30, respectively (Scheme 25). These organometallics by treatment with Br 2 in pyridine afforded the related gem-dibromoalkenes 28 and 31 in very high yields. 45 Recently, 1,1-dibromo-2-arylethenes have been readily obtained in good yields (66À90%) via double ipso-bromo desilylation with N-bromosuccinimide (NBS) of 1,1-bis(trimethylsilyl)-2arylethenes, which were in turn easily obtained in high yields by Heck coupling of aryliodides with ethene-1,1-diylbis(trimethylsilane) (Scheme 26). 46 Interestingly, 1,1-bis(trimethylsilyl)-2-alkenylethenes, for example, 1,1-bis(trimethylsilyl)-4-phenylbuta-1,3-diene, under the same reaction conditions led to the selective formation of the dibrominated products containing 1,3-diene fragments.A variety of gem-dibromides were prepared from stannyl acetylenes (Scheme 27). These compounds by treatment with 1.4 equiv of Cp 2 Zr(H)Cl generated the related 1,1-heterobimetallic species of tin and zirconium, which by brominolysis with 2.5 equiv of Br 2 in CCl 4 or 3.0 equiv of N-bromosuccinimide at room temperature gave the corresponding dibromides in 53À83% yields. 47 2.1.4. Miscellaneous Reactions. Nenajdenko and co-workers reported an efficient one-pot transformation of a wide range of aldehydes and ketones into the corresponding dibromoalkenes via intermediate formation of the related hydrazones (Scheme 28). 48 Thus, these carbonyl compounds were treated with hydrazine hydrate, and when the starting materials disappeared, CBr 4 and catalytic CuCl were added to give the target products in 43À97% yields from aldehydes 48a and 43À97% yields from linear, cyclic, and caged ketones, 48a depending on the steric hindrance of the staring material. Analogously, a wide range of hydrazones of (hetero)aryl alkyl ketones (electron-rich and electron-poor) was converted into the related dibromoalkenes in 23À92% yields. 48b The proposed mechanism of the reaction starts from the oxidation of CuCl with CBr 4 to give a Cu(II) salt, which in turn oxidizes the hydrazone to the diazoalkane (Scheme 28). Decomposition of the diazoalkane generates a copperÀcarbene complex, which by interaction with CBr 4 finally leads to the dibromoalkene.

show abstract

Section: Synthesis Of Gem-dihalovinyl Systemsmentioning

confidence: 91%

Section: Synthesis Of Gem-dihalovinyl Systemsmentioning

confidence: 99%

Section: Synthesis Of 11-dichloro-1-alkenesmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

2011

View full text Add to dashboard Cite

show abstract

“…Dichloroalkenes are highly attractive building blocks which can be modified by many ways . Literature approaches to the dichloroalkenes are mostly based on various modifications of the Wittig reaction (phosphorus ylides prepared from CCl 4 ‐PPh 3 , CBrCl 3 ‐PPh 3 , CHCl 3 ‐PPh 3 ‐ t BuOK, CCl 4 ‐P(NMe 2 ) 3 , and CBrCl 3 ‐P(NMe 2 ) 3 systems), the Wittig‐Horner reaction ((EtO) 2 P(O)CCl 2 Li) and β‐elimination reaction in α‐trichloromethyl carbinol acetates RCH(OAc)‐CCl 3 (rarely sulfonates) promoted by treatment with various reducing reagents (Zn, In, SmI 2, Pb/Al, RMgBr, CrCl 2 ).…”

Section: Introductionmentioning

confidence: 99%

Efficient Multigram Approach to Acetylenes and CF₃‐ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)

et al. 2020

View full text Add to dashboard Cite

A novel approach to terminal acetylenes based on catalytic olefination reaction COR of arylaldehydes to form dichloroalkenes followed by treatment with nBuLi was elaborated. This method is atom economical and displays high yields and effectivity. The corresponding alkynes can be prepared in up to 97 % yield. One pot procedure towards CF3‐ynones was elaborated to provide these products in up to 87 % yield starting from dichloroalkenes.

show abstract

ChemInform Abstract: RK. VON (TRICHLORMETHYL)‐CARBINYLTOSYLATEN MIT GRIGNARDREAGENTIEN

Reeve¹,

Brown²,

Steckel³

1971

Chemischer Informationsdienst. Organische Chemie

View full text Add to dashboard Cite

show abstract

Reaction of (trichloromethyl)carbinyl tosylates with Grignard reagents

Cited by 8 publications

References 1 publication

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Efficient Multigram Approach to Acetylenes and CF₃‐ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)

ChemInform Abstract: RK. VON (TRICHLORMETHYL)‐CARBINYLTOSYLATEN MIT GRIGNARDREAGENTIEN

Contact Info

Product

Resources

About

Reaction of (trichloromethyl)carbinyl tosylates with Grignard reagents

Cited by 8 publications

References 1 publication

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Efficient Multigram Approach to Acetylenes and CF3‐ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)

ChemInform Abstract: RK. VON (TRICHLORMETHYL)‐CARBINYLTOSYLATEN MIT GRIGNARDREAGENTIEN

Contact Info

Product

Resources

About

Efficient Multigram Approach to Acetylenes and CF₃‐ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)