Synthesis of Tetrasubstituted Alkenes by Stereo- and Regioselective Stannyllithiation of Diarylacetylenes

Abstract

Addition of trimethylstannyllithium to a diarylacetylene takes place exclusively in an anti-fashion to produce a lithio vinylstannane intermediate. The regioselectivity of the addition is controlled by the steric and electronic property of the acetylene and reaches up to >99:1. The two newly formed C-metal bonds can be sequentially and stereospecifically transformed into two new C-C bonds as illustrated by stereoselective synthesis of 4-hydroxytamoxifen and its regioisomer. A tetraarylethene bearing different aryl groups can be synthesized similarly and cyclized to a substituted dibenzo[g,p]chrysene derivative via a palladium-catalyzed arylation reaction.

Synthesis of extended polycyclic aromatic hydrocarbons by oxidative tandem spirocyclization and 1,2-aryl migration

“…Inspired by this observation, we anticipated that if a radical cation forms selectively at the alkene moiety of BPMF by employing appropriate single-electron oxidation systems, the subsequent spirocyclization and 1,2-aryl migration tandem process may take place to give the desired twisted molecule dibenzo[ g , p ]chrysene (DBC), which is an intriguing holding block of discotic molecules, fluorescent and charge carrier-transporting materials. Diverse synthetic methods of the DBC derivatives have been reported, such as oxidation of electron-rich bis(biaryl)acetylenes, oxidation of electron-rich tetraarylethylenes, intramolecular aromatic C–H/C–Br coupling, double Suzuki-Miyaura coupling, and Pd-catalysed coupling of C–H bonds of small PAHs with dimethyldibenzosilole13141519202122232425262728. On the basis of our reaction design, we herein describe a novel dehydrogenative PAH synthetic methodology based on the oxidative spirocyclization and 1,2-aryl migration tandem process.…”

Synthesis, Crystal Packing, and Ambipolar Carrier Transport Property of Twisted Dibenzo[g,p]chrysenes

“…First, addition of trimethylstannyllithium to (4‐methoxyphenyl)phenylacetylene afforded a (2‐stannylvinyl)lithium intermediate in 100 % stereoselectivity and 91:9 regioselectivity, as described in the top equation. This was confirmed by NMR spectroscopic analysis of the protonated and arylated products 12. This intermediate was then converted into triarylstannyl alkenes using the Negishi cross‐coupling reaction, as shown in the second equation.…”

“…10 We recently reported a new synthetic method that relies on a selective regio‐ and stereoselective stannyllithiation reaction to diarylacetylenes that is followed by palladium‐catalyzed coupling and condensation reactions 11. This method is potentially applicable to the synthesis of DBCs possessing both electron‐donating and electron‐withdrawing substituents, thus expanding the synthetic scope for DBCs derivatives 12. In the present work, we experimentally demonstrate the versatility of this new approach, describe the crystal packing of DBCs, and discuss their properties, including the ambipolar carrier mobility.…”

Regio- and stereoselective synthesis of tetra- and triarylethenes by N-methylimidodiacetyl boron-directed palladium-catalysed three-component coupling

“…Platform synthesis is a powerful strategy to realize the synthesis of complex molecules in a programable and diversity-oriented format. In this regard, the advances of metal catalysis have inspired tremendous efforts towards modular tetraarylethene construction starting from alkenes [11][12][13][14][15][16][17] or alkynes [18][19][20][21][22][23][24][25][26] . Nevertheless, lengthy synthetic operations, the poor functional group tolerance arising from the participation of organolithium or Grignard reagents, and the often-encountered poor regioselectivity strongly limits their practical application.…”