Ir-catalyzed ortho-directed C-H borylation of pyrazolylaniline (PZA)-modified arylboronic acids with bis(pinacolate)diboron afforded o-benzenediboronic acids in which two boronyl groups are differentially modified by pinacol (PIN) and PZA. By using this borylation after nondirected Ir-catalyzed C-H borylation, o-benzenediboronic acids are conveniently synthesized from unfunctionalized arenes. The differentially modified o-benzenediboronic acids undergo selective oxidation and Suzuki-Miyaura cross-coupling at the PZA-modified boronyl groups, affording o-functionalized arylboronic acids selectively.

Pyrazolylaniline serves as a temporary directing group attached to the boron atom of alkylboronic acids in Ircatalyzed C(sp 3 )−H borylation. The reaction takes place at α-, β-, and γ-C−H bonds, giving polyborylated products including di-, tri-, tetra-, and even pentaborylalkanes. α-C−H borylation was generally found to be the preferred reaction of primary alkylboronic acid derivatives, whereas βor γ-borylation also occurred if βor γ-C−H bonds were located on the methyl group.

Oligo(naphthalene-2,3-diyl)s were synthesized by iterative cross-coupling of 1,8-diaminonaphthalene-modified 3-iodo-2-naphthylboronic acids prepared from naphthalenes via Ir-catalyzed C–H borylation, Ru-catalyzed ortho-C–H silylation directed by an anthranilamide-modified boronyl group, and subsequent iododesilylation. The introduction of a chiral diol to the retained terminal boronyl group allowed selective induction of P- or M-helical conformations.

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Temporary modification of a boronyl group with pyrazorylaniline allowed insertion of arylpropiolates and diphenylacetylenes into the o-CH bond of arylboronic acids in the presence of rhodium catalysts, giving 3,3-diarylacrylates and triarylethene containing aryl groups bearing an o-boryl group stereoselectively. The boronyl group in the 3,3-diarylacrylates was converted into various functional groups, including chlorine, hydrogen, hydroxy, and aromatic groups. Keywords: C-H activation | Rhodium catalyst | Convertible directing groupDirected or nondirected addition of an aromatic CH bond across carboncarbon multiple bonds is recognized as one of the most efficient synthetic methods for arylethene and styrene derivatives.1 In particular, directed CH alkenylation has attracted much attention because it allows the highly regioselective introduction of organic groups into the o-position of the directing group. Since the establishment of Murai's Rucatalyzed, carbonyl-directed alkenylation, 2 a variety of directing groups in combination with various transition metals, including Ru, 3 Rh, 4 Ir, 5 and Pd 6 have been developed for o-CH alkenylation. However, this strategy significantly limits the substrate scope, when the directing group is not removable or convertible. To overcome this limitation, much attention has been focused on the development of convertible or traceless directing groups, 7 such as triazene 4f and carboxylic acid 3o groups. However, those convertible directing groups often lack high versatility in the subsequent transformations. Therefore, it is highly desirable to establish directing groups that can be converted into a variety of functional groups. We have established pyrazorylaniline (PZA) 8 and anthranilamide (AAM) 9 as easily attachable and detachable directing groups for directed CH functionalization reactions. In these studies, the PZA-modified boronyl group (Bpza) served as an o-directing group, which could be utilized for further transformations by the versatile reactivity of the boronyl group. However, the use of PZA has so far been limited to Ru-catalyzed o-CH silylation 8a and Ir-catalyzed o-CH borylation. 8c Our current focus is on the utilization of temporary directing groups such as PZA and AAM in o-CH addition to carboncarbon multiple bonds. In this work, we demonstrate the addition of o-CH bonds of arylboronic acids to arylpropiolates, which provides 3,3-diarylacrylates bearing two different aryl groups, one of which has an o-boryl group. Unsymmetrical 3,3-diarylacrylates are utilized as key starting materials for asymmetric reactions for the synthesis of enantioenriched 3,3-diarylpropanoates.10 Although stereoselective synthesis of unsymmetrical 3,3-diarylacrylates has been accomplished through several reactions, 11 such as MizorokiHeck-type reactions of cinnamate 12 and the Cu-catalyzed conjugate addition of arylboronic acid to alkynoate, 13 only a few examples of regioselective synthesis of o-functionalized 3,3-diarylacrylate have been reported. Herein, we report Rh-catalyzed o-C...