A catalytic system comprised of Pd(OAc)(2) and bidentate ligand dppe enabled first direct arylations with moisture-stable aryl sulfamates as electrophiles, and proved applicable to unprecedented C-H bond functionalizations with easily accessible alkenyl phosphates as well as benzyl phosphates.
An air-stable, well-defined palladium complex derived from secondary phosphine oxide (SPO) (1-Ad)(2)P(O)H enabled efficient C-H bond functionalizations with ample scope, which set the stage for direct arylations and benzylations of (benz)oxazoles, as well as unprecedented palladium-catalyzed C-H bond arylations on nonaromatic oxazolines.
Inexpensive copper catalysts allow for efficient syntheses of N-aryl-, N-acyl-, or N-H-(aza)indoles starting from ortho-alkynylbromoarenes. The broad scope of this domino N-arylation/hydro-
Efficient direct arylations of indoles occurred highly regioselectively at position C-3 with an in situ generated palladium complex derived from an air-stable HASPO, which enabled syntheses of diversely functionalized indoles, also with sterically hindered substrates.
A novel and simple one-step approach for the construction of optically active steroids in a highly stereoselective manner by using organocatalysis is presented. The reaction of (di)enals with cyclic dienophiles in the presence of a TMS-protected prolinol catalyst leads to the construction of important 14 β-steroids. This new reaction allows an easy access to optically active steroids with a variety of substituents in the A ring in high yields and up to greater than 99 % ee. The reaction has been extended to include the construction of B- and D-homosteroids as well as steroids containing heteroatoms in the B ring. The angular substituent at C13 can be varied and alkyl, ester, and sulfone functionalities are introduced with excellent stereoselectivities. Simple synthetic procedures provide access to a range of naturally occurring steroids such as estrone and related analogues.
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