TRACELESS DIRECTING GROUPS IN RADICAL CASCADES: FROM OLIGOALKYNES TO FUSED HELICENES WITHOUT TETHERED INITATORS

摘要

The present disclosure is directed to a traceless directing group in a radical cascade. The chemo- and regioselectivity of the initial attack in skipped oligoalkynes is controlled by a propargyl alkoxy moiety. Radical translocations lead to the boomerang return of radical center to the site of initial attack where it assists to the elimination of the directing functionality via β-scission in the last step of the cascade. In some aspects, the reaction of the present invention is catalyzed by a stannane moiety, which allows further via facile reactions with electrophiles as well as Stille and Suzuki cross-coupling reactions. This selective radical transformation opens a new approach for the controlled transformation of skipped oligoalkynes into polycyclic ribbons of tunable dimensions.

主权项

1. A method of preparing a polycyclic aromatic compound, the method comprising:
contacting a compound having structure (I) with a stannane compound in the presence of a radical initiator to thereby prepare the polycyclic aromatic compound; wherein the polycyclic aromatic compound has a structure (1-a) as follows: wherein the compound having structure (I) is as follows: and further wherein: each R is independently selected from the group consisting of hydrogen, halogen, cyano, C1-C6 alkyl, and C1-C6 alkoxy; R1 is selected from the group consisting of C1-C6 alkyl, —CH2OCH3, and —CH2CH2OCH3; X is a C1-C6 alkyl or phenyl; n1 and n2 each independently have a value between 0 and 50, and further wherein either n1 and n2 have the same value or n1=n2+1; and n3 has a value of n1+n2.