Intramolecular Morita–Baylis–Hillman and Rauhut–Currier reactions. A catalytic and atom economic route for carbocycles and heterocycles

Abstract

Review: [88 refs.

Enantioselective Rauhut–Currier‐Type 1,6‐Conjugate Addition of Methyl Vinyl Ketone to para‐Quinone Methides

“…The Rauhut-Currier (RC) reaction, also known as the vinylogous Morita-Baylis-Hillman reaction, describes the coupling of an electron-deficient olefin to as econd Michael acceptor. [1,2] The RC reactioni sa ne fficient, atom-economical strategy to constructc arbon-carbon bonds and densely functionalized molecules. [3] Despite its early discovery in 1963, it was not until 2002 that the first asymmetric RC reaction was unveiled.…”

“…Notably, phosphines are also elegant catalysts for the RC reaction. [2] Therefore, chiral organocatalysts incorporating ap hosphine and aB rønsted acid could be used for RC-type 1,6-conjugate addition of p-QMs. Here, we report the first enantioselective RC-type1 ,6-conjugate addition of methyl vinyl ketone (MVK) to p-QMs.…”

Chemo‐ and Stereoselective Cross Rauhut–Currier‐Type Reaction of Tri‐substituted Alkenes Containing Trifluoromethyl Groups

“…Substrates with nearly any substitution at the ortho-, meta-, or para-position on the Scheme2.Synthetic strategy. aromatic groups of nitroolefin 2 gave the desired products in moderate to good yields andh igh Z/E ratios (Table2,e ntries [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Higher yields and Z/E ratios were obtained when the nitroolefin 2 bearing electron-donating groups (entries 3-9 (see Figure 2f or ORTEP figures of 3i and 3i')r ather than electron-neutral or -withdrawing groups (entries 1and 11-18).…”

“…2018, 24,1947 -1955 www.chemeurj.org of 72 %yield and 83 % ee (entry 8). Combining bisthiourea catalyst C9 with alkaloids C1 or C8 did not improvee nantioselectivity (entries 9-10), nor did stereoselectivity improve with different solvents (entries1 [1][2][3][4][5][6][7][8][9][10][11][12][13][14], reactiont emperatures or catalyst loadings( entries [15][16][17]. We proposet hat the asymmetricR C-type reactioni nt he case of the most powerful bifunctional H-bonding-tertiary amine catalyst involves the transition state shown in Figure 5, reflecting ap ossible Brønsted acid-Lewis base activation mode.E SI-MS analysis of reaction mixtures revealed intermediates of catalyst C8 predicted by our catalytic cycle.…”

“…[2] Much more challenging is the so-called" cross-Rauhut-Currier" reaction between two different activated alkenes, which normally proceeds with poor selectivity. [3] Cross-RCr eactions have been extensively explored between am ono-substituted alkene and another electron-deficienta lkene (Scheme 1a), [4] as well as between a1 ,2-disubstituted alkene and anothere lectron-deficient alkene (Scheme 1b). [5] Previous studies have demonstrated that 1,2,2-tri-substituted alkenes are poor donors in cross-RC reactions, likely because of steric hindrance,w hich means that few methods exist to generate tetra-substituted RC-type products (Scheme1c).…”