Ligand Effects on the Stereochemical Outcome of Suzuki–Miyaura Couplings

Abstract

The ligands associated with various Pd catalysts play a crucial role in determining the stereochemistry of cross-couplings between boronic acids and Z-alkenyl halides. A ligand on palladium has been found that leads to the desired products under mild conditions and in high yields that, in most cases, retain their Z-olefin geometry.

Copper(I)‐Catalyzed (Z)‐β‐(Tosyloxy)alkenyl Iodide Synthesis from (Aryl)[(E)‐β‐(tosyloxy)alkenyl]iodonium Tosylates: Diversity‐Oriented Synthesis of Trisubstituted Alkenes

“…Addition of external iodine did not increase the rate of the reaction, and product 2a was obtained in a similar yield. Accordingly, compound 2a was subjected to Suzuki-Miyura coupling under the modified conditions of Lipshutz [18] to furnish 3 and 4 stereoselectively by using different boronic acids (Scheme 4). did not alter the course of the reaction.…”

Bidirectional Hiyama–Denmark Cross‐Coupling Reactions of Bissilyldeca‐1,3,5,7,9‐pentaenes for the Synthesis of Symmetrical and Non‐Symmetrical Carotenoids

“…21-7.17 (m, 2H;A rH), 7.07-6.95 (m, 3H;A rH), 6.86 (d, J = 18.8 Hz, 1H), 6.73 (d, J = 18.8 Hz, 1H), 6.69-6.60 (m, 2H), 6. 30-6.20 (m, 2H) (18), 341 (13), 301 (15), 270 (19), 242 (18) (1E,3E,5E,7E,9E)-10-Benzyldimethylsilyl-benzyl-10-(ethoxydimethylsilyl) -3,8-dimethyldeca-1,3,5,7,9-pentaene) (21) To ac ooled (0 8C) solution of 19 (0.65 g, 1.72 mmol) in MeOH (7.8 mL), K 2 CO 3 (2.85 g, 20.60 mmol) was added. The mixture was stirred at 25 8Cf or 1hand water was added.…”

“…After purification by column chromatography (CNsilica gel, 98:2 hexane/EtOAc), 4.5 mg (32 %) of an orange oil identified as 9-cis-b,b-carotene 9 were isolated. 1 HNMR (400.13 MHz, CDCl 3 ): d = 6.74 (dd, J = 14.8, 11.6 Hz, 2H), 6.68 (d, J = 7.9 Hz, 1H), 6.66-6.54 (m, 3H), 6.28 (d, J = 14.9 Hz, 1H), 6.26-6.19 (m, 2H), 6.19-6.08 (m, 4H), 6.05 (d, J = 11.5 Hz, 1H), 2.08-1.99 (m, 4H), 1.97 (s, 6H), 1.95 (s, 6H), 1.76 (s, 3H), 1.71 (s, 3H), 1.66-1.59 (m, 4H), 1.51-1.39 (m, 4H), 1.04 (s, 6H), 1.03 ppm (s, 6H); 13 , [40] TBAF (0.33 mL, 0.33 mmol, 1 m in THF) was added to ac ooled (0 8C) solution of 23 (72 mg, 0.145 mmol) in THF (1.3 mL). After stirring for 30 min at 0 8C, asolution of 25 (40 mg, 0.126 mmol) in THF (1.3 mL) and [Pd 2 dba 3 ]·CHCl 3 (13 mg, 0.013 mmol) were added, and the reaction mixture was stirred at 0 8Cf or 1h and at 25 8Cf or…”

Iridium‐Catalyzed, Diastereoselective Dehydrogenative Silylation of Terminal Alkenes with (TMSO)2MeSiH

“…Although vinylarenes can be accessed from terminal alkenes through the Heck reaction [16] or direct arene vinylation, [17] the method we report here produces the Z isomer as the major product, whereas the Heck reaction produces the E isomer. Alternative routes by Suzuki coupling require the Scheme 1.…”