Reductive alkylation of perfluorocarboxylic acid esters with CCl3F or CCl4 and synthesis of higher linear perfluoroketones

Addition of CFCl3 to Aromatic Aldehydes via in Situ Grignard Reaction

“…Prior to our previous report [15], the addition of CFCl 3 to carbonyl groups was mainly constrained to highly activated carbonyl compounds such as perfluoro carboxylic acid esters and aromatic carbonyl entities attached to fluoro or trifluoromethyl moieties [9,17]. Even after activation with trifluoromethyl or fluoro aromatic substituents, the isolated product yields were only modest (58%–79%) and low (39%) for un-activated substrates such as benzaldehdye [9,17]. Hu et al succeeded in obtaining dichlorofluoromethyl alcohols by reaction of CFCl 3 with less electrophilic ketones using magnesium/lithium chloride as catalysts [22].…”

“…Carbenoid intermediates containing fluorine substituents are highly unstable, and methods for obtaining higher yields of products using these intermediates have been successful only in cases where the carbonyl groups are activated by electron withdrawing groups [9,17] or by employing unconventional activating methods such as ultrasonic irradiation [15]. Temperature also plays a very important role in these reactions [22,29].…”

“…This scenario led to the development of a new research field, i.e. , cost-effective and synthetic utilization of CFCs for the synthesis of novel and non-hazardous fluorinated compounds [5,6,7,8,9,10,11,12,13]. Out of the many CFCs, CFCl 3 or trichlorofluoromethane (CFC-11) has the maximum ozone depletion potential [14].…”

Polyfluorinated Ethanes as Versatile Fluorinated C2-Building Blocks for Organic Synthesis

“…Organomercury intermediates were generated in R F X–HgBr 2 –Al system. The addition of these organometallics to hexafluoroacetone and ethyl pentafluoropropanoate led to fluorinated alcohol 203o and bis­(pentafluoroethyl)­ketone 222d ′, respectively (Scheme ).…”

Reactions of polyfluorinated thietanes

“…For example, recently Zeifman and Postovoii employed an Al/HgCl 2 system for alkylation of polyfluorinated ketones [20,[23][24][25] and esters [26] by CCl 4 , FCCl 3 and CF 3 CCl 3 and also reported a very interesting reductive defluorination process under action of Al/HgCl 2 on fluorinated ketones leading to the formation of polyfluorinated enols after acidic hydrolysis [27,28].…”