Rhodium-Catalyzed Asymmetric 1,4-Addition of α,β-Unsaturated Imino Esters Using Chiral Bicyclic Bridgehead Phosphoramidite Ligands

Abstract

A chiral bicyclic bridgehead phosphoramidite (briphos) prepared from 1-aminoindane is a highly efficient and selective ligand for rhodium(I)-catalyzed asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated N,N-dimethyl-sulfamoyl imino esters at ambient temperature. This transformation provides a new class of chiral (Z)-γ,γ-diaryl-α,β-dehydroamino esters with excellent yield and enantioselectivity.

[Retracted] Enantioselective Rh- or Ir-catalyzed Directed C(sp3)–H Borylation with Phosphoramidite Chiral Ligands

“…The use of chiral P-backbones bearing VAPOL [(S,S,S)-L6], spirobiindanyl [(R,R,R)-L7], or TADDOL [(R,R,R,R)-L8] proved ineffective in the improvement of the enantioinduction while maintaining good to excellent reactivity (6590% yields, ¹28 to 25% ees). A chiral phosphoramidite (S)-L9 based on a bicyclic bridgehead structure showed some reactivity towards the borylation reaction, 13 but its asymmetric induction proved to be inferior to (S,S,S)-L4 (11% ee vs. 31% ee).…”

Enantioselective synthesis of gem-diarylalkanes by transition metal-catalyzed asymmetric arylations (TMCAAr)

“…In 2015, Kim and co-workers 11 reported an elegant Rh-catalyzed asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated N , N -dimethylsulfamoyl imino esters with a new bicyclic bridgehead phosphoramidite ligand ( L3 ). Chiral ( Z )-γ,γ-diaryl-α,β-dehydroamino esters were afforded with excellent yields and enantioselectivities (75–96% ee) ( Scheme 6 ).…”

Rh-Catalyzed Highly Enantioselective Synthesis of Aliphatic Sulfonyl Fluorides

“…The Rh/binap catalyzed asymmetric addition of arylboronic acids to conjugated enones was firstly reported by Hayashi and Miyaura in 1998 (Takaya et al., 1998). This pioneering method has been rapidly developed in addition to various functional groups attached alkenes such as α,β -unsaturated esters (Duchemin and Cramer, 2019, Paquin et al., 2005a, Paquin et al., 2005b, Sakuma et al., 2000), amides (Yuan and Sigman, 2018, Wang et al., 2014, Hargrave et al., 2006, Sakuma and Miyaura, 2001, Senda et al., 2001), carbonyl (Bocknack et al., 2004, Kadam et al., 2017, Khiar et al., 2013, Moragues et al., 2015, Paquin et al., 2005a, Paquin et al., 2005b, Shintani et al., 2006, Yasukawa et al., 2015), phosphonates (Hayashi et al., 1999), imines (Cui et al., 2011, Jagt et al., 2006, Lee and Kim, 2015, Nishimura et al., 2012a, Nishimura et al., 2012b, Shintani et al., 2010, Trincado and Ellman, 2008, Wu et al., 2018), sulfonyl (Lim and Hayashi, 2015, Liu et al., 2019, Mauleon and Carretero, 2005, Nishimura et al., 2012a, Nishimura et al., 2012b, Takechi and Nishimura, 2015, Yan et al., 2019), nitro compounds (Wang et al., 2010, Hayashi et al., 2000, He et al., 2015, Miyamura et al., 2017), borylalkenes (Sasaki and Hayashi, 2010), and other electron-deficient alkenylarenes (Pattison et al., 2010, Saxena and Lam, 2011). We envision that through using Rh(I) catalyst and appropriate chiral ligand, the reaction of 2-arylethenesulfonyl fluorides with arylboronic acids would furnish a class of novel chiral molecules bearing both chiral gem-diarylmethane moiety and sulfonyl fluoride functionality (Scheme 1).…”