Asymmetric Allylboration of Aldehydes and Ketones Using 3,3‘-Disubstitutedbinaphthol-Modified Boronates

Abstract

Allylboronates derived from 3,3'-disubstituted 2,2'-binaphthols react with aldehydes and ketones to give the expected allylated products with up to >99:1 er. Highest selectivities were observed for aromatic ketones. The bis(trifluoromethyl) derivative is particularly outstanding in terms of reactivity, selectivity, and robustness. [reaction: see text]

A Broadly Applicable Copper Reagent for Trifluoromethylations and Perfluoroalkylations of Aryl Iodides and Bromides

“…Previous syntheses of 3,3'-(CF 3 ) 2 -binol have required superstoichiometric amounts of Burtons CuCF 3 reagent or generate stoichiometric amounts of SO 2 and MeI. [16,17] Complex…”

An Unprecedented Rhodium‐Catalyzed Asymmetric Intermolecular Hydroacylation Reaction with Salicylaldehydes

“…Representative Procedure (RP4) for the exo-Selective Hydroacylation Reaction using Norbonene Step 1, (R)-2,2'-Bis(methoxymethoxy)-3,3'-bis(4-(trifluoromethyl)phenyl)-1,1'-binaphthyl [(R)-40]: This compound was prepared by the procedure of Chong: [28] (R)-3,3'-dibromo-2,2'-bis(methoxymethoxy)-1,1'-binaphthyl [600 mg, 1.13 mmol, 1.0 equiv.] and [PdA C H T U N G T R E N N U N G (PPh 3 ) 4 ] (130 mg, 0.113 mmol, 10 mol %) were placed in a Schlenk tube and dissolved in DME (7.5 mL).…”

“…Step 2, (R)-3,3'-Bis[4-(trifluoromethyl)phenyl]-1,1'-binaphthyl-2,2'-diol [(R)-41]: This compound was prepared by the procedure of Chong: [28] (R)-2,2'-bis(methoxymethoxy)-3,3'-bis(4-(trifluoromethyl)phenyl)-1,1'-binaphthyl [(R)-40, 554 mg, 0.836 mmol, 1.0 equiv.] was dissolved in THF/ MeOH (1:1 v/v, 20 mL).…”

The First Asymmetric Halogen/Metal‐Exchange Reaction: Desymmetrization of Alcohols with Enantiotopic Bromoarene Substituents

“…They were synthesized as detailed below-as were the known compounds 18 a [29] and 19 a [30] and, on a new route, the equally known compound [31] …”

“…This rendered 92 % of the bis(methoxymethyl ether 22. [29] Bis(ortho-lithiation) of 22 with nBuLi/TMEDA followed by iodination provided diiodide 23 [29] in 84 % yield (in the absence of TMEDA, these steps furnished only 49 % of 23 rather than 88 % as reported [29] ). A 1:2 Suzuki coupling between diiodide 23 and 2.6 equiv of PhB(OH) 2 followed by removal of the MOM groups through transacetalization with methanol/H 2 SO 4 led to the phenylated binaphthol 18 a in 89 % yield over the two steps.…”