A new and practical synthesis of vinyl dichlorides via a non-Wittig-type approach

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

“…It should be noted, that only very rare examples of conversion of dichloroalkenes into acetylenes can be found in the literature. [10a], [11c], We found that treatment of dichloroalkenes 3 with two equivalents of n BuLi at –70 °C followed by acidic work up led to terminal acetylenes 7 in high yields. For example, alkyne 7b was isolated in 97 % yield.…”

“…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 ).…”

Synthesis of terminal alkynes based on (1S,3R,4R)- and (1S,3S,4R)-2-azabicyclo[2.2.1]heptane

“…The advantage of this route lies in the fact that the reaction is carried out without phosphorous derivatives offering lower toxicity of the reaction mixture and of impurities as compared to Wittig-type reactions. 11,12 The reaction of aldehyde 4 gave the dichloroalkene (1S,3R,4R)-6 in a moderate yield (32%) (Scheme 2). In the next step, the dichloroalkene 6 was subjected to elimination conditions.…”

Olefination of carbonyl compounds: modern and classical methods

“…145 The corresponding alcohols are prepared by condensation of aldehydes with chloroform in the presence of phase-transfer catalysts 8,145 or by a reaction of aldehydes with the trichloromethyl anion generated from trichloroacetic acid. 146 gem-Bromochloroalkenes and gem-dibromoalkenes can be prepared by a similar procedure using dibromochloromethane and bromoform, respectively. 147 Thus the addition of the tribromomethyl anion to ethyl phenyl ketone results in tribromomethylpropanol 225.…”