A series of novel, efficient, air-stable, and tunable chiral bisdihydrobenzooxaphosphole ligands (BIBOPs) were developed for rhodium-catalyzed hydrogenations of various functionalized olefins such as alpha-arylenamides, alpha-(acylamino)acrylic acid derivatives, beta-(acylamino)acrylates, and dimethyl itaconate with excellent enantioselectivities (up to 99% ee) and reactivities (up to 2000 TON).
Simple and practical asymmetric synthesis of functionally differentiated aminoindanol based endo-N-sulfonyl 1,2,3-oxathiazolidine-2-oxide as sulfinyl transfer agents are developed. The importance of these new and unique sulfinyl transfer reagents are exemplified by the expedient production of several sulfinamide ligands, including either enantiomer of (R)-tert-butanesulfinamide in excellent yields and enantiopurities.
A general, efficient, and highly diastereoselective method for the synthesis of structurally and sterically diverse P-chiral phosphine oxides was developed. The method relies on sequential nucleophilic substitution on the versatile chiral phosphinyl transfer agent 1,3,2-benzoxazaphosphinine-2-oxide, which features enhanced and differentiated P-N and P-O bond reactivity toward nucleophiles. The reactivities of both bonds are fine-tuned to allow cleavage to occur even with sterically hindered nucleophiles under mild conditions.
Biaryl monophosphorus ligands containing a 2,3‐dihydrobenzo[d][1,3]oxaphosphole framework are highly effective for the palladium‐catalyzed Suzuki–Miyaura cross‐coupling reactions of a wide range of substrates. Ligand 1 has demonstrated excellent performance for coupling reactions of extremely hindered arylboronic acids.
Recently we have reported reaction protocols for the catalytic asymmetric allylation (CAA reaction) of aldehydes using allylstannanes and chiral Lewis acid catalysts prepared from (R)-or (5>BINOL and Ti(0-i'-Pr)4.1 These procedures have proven remarkably efficient and especially convenient, since the chiral catalysts are prepared very simply in ca. 1 h from commercially available reagents. As the enantioselectivity exhibited in these reactions would appear to be derived solely from the structure of the chiral Lewis acid-aldehyde complex, it seemed obvious that other Lewis acid promoted reactions might be susceptible to enantioselective catalysis using the same procedures. We record herein the development of methodology using these catalysts for the catalytic enantioselective Mukaiyama aldol condensations2 of 1 -(ferf-butylthio)-1 -((trimethylsilyl)oxy)ethene with aldehydes to give /3-hydroxy thiol esters in high yields and with excellent enantiomeric excesses.3 In
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