Recent chemistry of benzocyclobutenes

Abstract

The photochemically induced Wolff rearrangement has proved to be an excellent method for the preparation of BCB derivatives-by a ring contraction protocol-which are otherwise dif®cult to prepare. Thus, the a-diazoindanones 48 undergo a ring contraction reaction under a Scheme 13. Scheme 14. Scheme 15. Scheme 16.

2‐Hydroxybenzocyclobutenone Ethylene Dithioacetals as Precursors of Highly Substituted 1,4‐Dihydronaphthalenes

“…The aqueous phase was separated and extracted with toluene (3 ϫ 3 mL). The combined organic layers were washed with brine (10 mL) and dried with Na 2 SO 4 . Removal of the solvent in vacuo followed by flash chromatography (PE/EtOAc, 10:1) gave the products 9c,d, 11b, 12b, and 15a, respectively.…”

“…[4] We are interested in 1,4-dihydronaphthalenes because we envisage spiro derivatives 2 as intermediates en route to thionaphthoquinones 1 (Scheme 1). In fact, we have previously shown that 1,3-dithiolane S-oxides can be converted into thioaldehydes and -ketones by silylation and subsequent deprotonation.…”

Expanding the Diversity of Polycyclic Aromatics Through a Suzuki–Miyaura Cross‐Coupling Strategy

“…[21] Furthermore, the aldehyde functionality present in 20d can be used for additional synthetic elaboration. Scheme 6. To prepare unsymmetrical 9,10-diarylanthracene derivatives, [20] compound 19 was treated with 1.5 equivalents of thien-2-ylboronic acid under the same reaction conditions to generate 9-bromo-10-(thien-2-yl)anthracene (22) in 79% isolated yield (Figure 3). Selective SM reactions with other heteroarylboronic acids were attempted next, and typically 61-90 % yields of the monocoupled products 21-25 were obtained.…”

The First Benzo[1,2:4,5]dicyclobutenones and Their Tricarbonylchromium Complexes

“…[1][2][3][4][5][6][7][8] The striking feature of benzocyclobutenes is the potential for ring-opening reactions leading to reactive ortho-quinodimethanes, which readily enter into cycloaddition reactions. In order to eliminate the planes of symmetry present in ortho-quinodimethanes, metal π complexes of benzocyclobutene and substituted derivatives have been prepared and investigated, both by ourselves and by Kündig's group.…”