A Mechanism Study for Self-Cleaving Chlorotetrafluoroethylsulfinyl (-SOCF2CF2Cl)-Directed Pd(II)-Catalyzed C-H Activation.

A mechanism study for Pd(II)-catalyzed C(sp3)-H activation using a self-cleaving chlorotetrafluoroethylsulfinyl (-SOCF2CF2Cl) auxiliary as a directing group is reported. Mechanistic studies reveal that (1) the auxiliary group is crucial for C(sp3)-H activation, (2) the reaction undergoes a C(sp3)-H olefination-Michael addition-removal of the auxiliary sequence, (3) the removal of the auxiliary (SORf) is most likely the alcoholic solvolysis of the -SOCF2CF2Cl group on the N-tri-substituted sulfonamides, and (4) the C(sp3)-H cleavage is involved in the rate-determining step.

Synthesis of γ-Lactams via Pd(II)-Catalyzed C(sp3)-H Olefination Using a Self-Cleaving Polyfluoroethylsulfinyl Directing Group.

A monodentate directing group, 2-chlorotetrafluoroethylsulfinylmide (-NHSOCF2CF2Cl), for inert C(sp3)-H bond activation is reported. This directing group shows efficient ability in Pd(II)-catalyzed C(sp3)-H olefination. The desired olefination products undergo subsequent Michael addition and in situ expulsion of the auxiliary to provide the free NH γ-lactam products. Preliminary mechanistic studies reveal that the auxiliary group is crucial for C(sp3)-H activation.

Synthesis of N-H-Free 1,4-Dihydroisoquinoline-3(2H)-ones via Pd-Catalyzed C-H Olefination Using Polyfluorosulfinyl as the Auxiliary Group.

A Pd(II)-catalyzed olefination of aryl C-H bonds with a self-cleaving 2-chlorotretafluoroethylsulfinyl (-SOCF2CF2Cl) auxiliary was developed. In the reaction mixture, the olefination products underwent in situ Michael addition and the subsequent expulsion of the auxiliary to provide the N-H-free 1,4-dihydroisoquinoline-3(2H)-one products. Mechanistic studies reveal that the auxiliary group is crucial for C-H activation, and Na2CO3 and an alcoholic solvent play key roles in facilitating the cleavage of the polyfluoroalkylsulfinyl auxiliary.

Cu(II)-Catalyzed ortho-Selective Aminomethylation of Phenols.

A Cu(II)-catalyzed ortho-selective functionalization of free phenols with trifluoroborates to afford Csp2-Csp3 coupling products under mild conditions has been developed. A variety of functional groups on the phenol and the potassium aminomethyltrifluoroborate substrates were found compatible, furnishing the corresponding products in moderate to excellent yields. A single-electron transfer radical coupling mechanism involving a six-membered transition state is proposed to rationalize the high levels of ortho-selectivity in the reaction. This protocol provides straightforward access to ortho-aminomethyl-substituted phenols, unnatural amino acids and other bioactive small molecules.

5-[(2-Hy-droxy-eth-yl)(meth-yl)amino]-thio-phene-2-carbaldehyde.

In the title compound, C8H11NO2S, the aldehyde group is approximately coplanar with the thio-phene ring [maximum deviation = 0.023 (2) Å]. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds into supra-molecular chains propagating along the a-axis direction.