Lewis Acid Catalyzed Friedel–Crafts Alkylation of Alkenes with Trifluoropyruvates

Abstract

A Friedel-Crafts alkylation reaction of styrenes with trifluoropyruvates has been developed, which delivered allylic alcohols in excellent yields (up to 98%) using the Ni(ClO4)2·6H2O/bipyridine complex as a catalyst. The asymmetric reaction was catalyzed by the chiral Cu(OTf)2/bisoxazoline complex to afford the corresponding chiral allylic alcohols bearing trifluoromethylated quaternary stereogenic centers in moderate enantioselectivities (up to 75% ee).

Brønsted Acid Enabled Nickel‐Catalyzed Hydroalkenylation of Aldehydes with Styrene and its Derivatives

“…These alkenylmetal reagents are generally prepared in situ through the reaction of alkenylhalides with stoichiometric amounts or an excess of metallic reagents (Mg,L ia nd Zn), [2] through the reaction of alkenylhalides with aC rc atalyst and an excess of reductants (Nozaki-Hiyama-Kishi reaction), [3] or through the hydrometallation of alkyne with metallic hydride reagents. [8][9][10] In 2005, an important breakthrough was achieved in this regard by Jamison and coworkers, [11] who used the Lewis acid activator triethylsilyl triflate (TESOTf) to facilitate nickel-catalyzed direct cou-pling of unactivated alkenes mainly with aromatic aldehydes, affording as eries of highly branched-selective allylic alcohol derivatives (Scheme 1c). Despite these advances, the direct coupling reaction of abundantly available alkenes such as styrene and a-olefins with unactivated carbonyls to allylic alcohols is still highly desirable.N ot only are these alkenes readily available and inexpensive but such coupling would eliminate the use of external metallic reagents and reductants,t hereby leading to more atom-economical and environmentally friendly reactions.…”

Recent Advances in Catalytic Asymmetric Synthesis of Tertiary Alcohols via Nucleophilic Addition to Ketones

“…Apart from the aforementioned electron‐rich aromatic compounds such as indole, pyrrole and phenol, the less reactive simple olefins, a largely unexplored substrate class, were also demonstrated to be appropriate nucleophiles in asymmetric additions to 3,3,3‐trifluoropyruvate with the chiral bisoxazoline 136 ‐derived Cu(II) complex as catalyst (Scheme ) . This reaction provided an access to CF 3 ‐substituted chiral allylic alcohols 137 in 28–88% yields and 64–75% ee values.…”

Ni-catalyzed hydroaminoalkylation of alkynes with amines

“…A llylic amines not only widely exist in a broad range of natural products and bioactive compounds, but also serve as versatile building blocks in organic synthesis [1][2][3][4] . The development of efficient and general methods for their synthesis has received much attention during the past several decades [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . Among various reported methods, transition metal-catalyzed hydroaminoalkylation of π-unsaturated compounds, such as alkenes and alkynes represents one of the most straightforward and atom-economical synthetic routes [24][25][26][27][28][29][30][31] .…”