Science of Synthesis

Harris, P. A., Science of Synthesis Knowledge Updates, (2021) 3, 5.

A one-step synthesis of indolo[2,1-a]isoquinolines ‌8‌ uses a rhodium(III)-catalyzed triple C—H/N—H/C—H activation–annulation cascade of aryltriazenes ‌6‌ and insertion of 2 equivalents of a diarylalkyne ‌7‌, with the triazene acting as a cleavable directing group (‌Scheme 2‌).[‌1‌] Two reaction conditions were optimized for this procedure. When the diarylalkyne ‌7‌ is limited to 1 equivalent, the reaction produces a 2,3-diaryl-1H-indole (e.g., ‌14‌), which is also postulated as a likely intermediate in this cascade (‌Scheme 3‌). The rhodium(III)-catalyzed conversion of preformed 2,3-diaryl-1H-indoles into indolo[2,1-a]isoquinolines is described later in this chapter (see Section ‌10.24.1.1.2.1.2.1.3‌).

‌Meeeee 8‌ Meeeeeee ee Meeeeeeeeeeee eeee Meeeeeeeeeeee[‌8‌]

‌Meeeeeeeeee 8‌

Mee eeeeeeee ee eeeeeee ee eeeeeee ee eeeeeee eeeeeeeee ee e 8,8-eeeeee-8M-eeeeee (e.e., ‌88‌). M eeeeeeee eeeeeeeee eee eee eeeee eeeeeeeee eeeee eeeeeee ee eeee eeeeee ee eeeeeeeeeee ee ‌Meeeee 8‌ eeeee eeeeeeeeeeeeeeeee. Meeee, ee eeeeee eeeeeee(MMM) eeeeeee eeeeeee ee eeeeeeeee eeee eeeeeeee(η8-eeeeeeeeeeeeeeeeeeeeeeeeeee)eeeeeee(MMM) eeeee {[Me(Me*)Me8]8}, e eeeeee eeee, eee e eeeeee eeeeeee. Meee ee eeeeeeee ee e eeeeeeeeee M—M eeee eeeeeeeee eeeeeeee ee eee eeeeeee eeeeeeee eeee ee eee eeeeeeeeeeee ‌8‌ ee eeeeeee eeeeeee eeeeeee ‌88‌. Meeeeeeeeeee ‌88‌ eeee eeeeeeeee eeeeeeeeeeeeeeeee eeeeeeeee ee eeee eeeee-eeeeeeee eeeeeeeeee ‌88‌. Mee eeeeeeeeee ‌88‌, eeeeeeeeee eeeee eeeeeeee, eeeeeee eeeeeeeeee ee e eeee eeeeee eee-eeeeeeee eeeeeee eeeeeee ‌88‌ eee e 8,8-eeeeee eeeee. Meeeeeeee eeeeeeeeeee eeeeeeee eee 8,8-eeeeeeee-8M-eeeeee (‌88‌). Me ee eee eeeee eeeeeee eee eeeeeeeeee eeeeeeeee eeeeeee ee ‌88‌ eeeeeeeee eeeeeeeeee ee eee-eeeeeeee eeeeeee eeeeeee ‌88‌ eeeee ee ee eeeee eeeeeeeee eeeeeeeeeee. Mee eeeeeee M8—M8 eeee eeeeeeee eee ee eeeeeeee ee eeeeee eeee eeeeeeeee eeee eee M—M eeeeeeeeee. Meeeeeeeeeeee, M=M eeeeeeeee ee eee Me—M eeee ee eeeeeeeeee ‌88‌ eeeee eeeee eeeeeeeeeeee ‌88‌, eeeee ee eeeeeeeeee eeeeeeeee eee eeeeeeeeee, eeeee eeee eeeeeeee 8,8-eeeeeeee-8M-eeeeee (‌88‌). Mee eeeeee eeeeeeeee eee eee eeeeeeeeee eeeeeeeee eeeee eeeeeeeeee 8,8-eeeeeeee-8M-eeeeee (‌88‌) eeee e eeeeee eeeeeeeeeeeeeeeee eeee 8,8,88-eeeeeeeeeeeeeee[8,8-e]eeeeeeeeeeee (‌88‌) ee eeeeeeee ee eeee eeeeeeeee eee 8-eeeeee-8M-eeeeee ee Meeeeee ‌88.88.8.8.8.8.8.8.8‌ (‌Meeeee 88‌).

‌Meeeee 8‌ Meeeeeeee ee eee Meeeeeee ee Meeeeeeeeeeee eeee Meeeeeeeeeeee[‌8‌]

Meeeeeeeeeee Meeeeeeee

Meeeee[8,8-e]eeeeeeeeeeeee ‌8‌; Meeeeee Meeeeeeee:[‌8‌]

Me eeeeeeeeeeee ‌8‌ (8.8 eeee, 8.8 eeeee), [Me(Me*)Me8]8 (8.8 ee, 8 µeee, 8 eee%), Me(M8Me-Me)8 (888 ee, 8.8 eeee, 8.8 eeeee), eee MeMeM8 (88.8 ee, 8.88 eeee, 88 eee%) eeee eeeeeee eeee ee eeee-eeeee Meeeeee eeee. Mee eeee eee eeeeee, eee eeee eeeeeeeee eee eeeeeee eeee eeeee eeeee eeeee. M eeee ee e eeeeeeeeeeee ‌8‌ (8.8 eeee, 8.8 eeeee) ee MeMM/MeMe8MMM (8:8; 8.8 eM) eee eeeee eeeeeee eee eeeeeee eee eeeeeee. Mee eeeeeee eee eeeeeee eeeee eeeee ee 88 °M eee 88 e, eeee eeeeee ee ee, eee eeeeeeeeeeee ee eeeeee eeeeeeeeeee. Mee eeeee eeeeeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (eeeeee eee, MeMMe/eeeeeeeee eeeee 8:888 ee 8:88); eeeee: 88–88%.

Meeeee[8,8-e]eeeeeeeeeeeee ‌8‌; Meeeeee Meeeeeeee:[‌8‌]

Me eeeeeeeeeeee ‌8‌ (8.8 eeee, 8.8 eeeee), [Me(Me*)Me8]8 (8.8 ee, 8.8 µeee, 8 eee%), Me(MMe)8•M8M (88 ee, 8.8 eeee, 8.8 eeeee), eee MeMMe (88.8 ee, 8.888 eeee, 88 eee%) eeee eeeeeee eeee ee eeee-eeeee Meeeeee eeee. Mee eeee eee eeeeee, eee eeee eeeeeeeee eee eeeeeee eeee eeeee eeeee eeeee. M eeee ee e eeeeeeeeeeee ‌8‌ (8.8 eeee, 8.8 eeeee) ee 8,8-eeeeeeeeeeeeee (8.8 eM) eee eeeee eeeeeee eee eeeeeee eee eeeeeee. Mee eeeeeee eee eeeeeee eeeee eeeee ee 88 °M eee 88 e, eeee eeeeee ee ee, eee eeeeeeeeeeee ee eeeeee eeeeeeeeeee. Mee eeeee eeeeeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (eeeeee eee, MeMMe/eeeeeeeee eeeee 8:888 ee 8:88); eeeee: 88–88%.

References