CuI Mediated One-Pot Cycloacetalization/Ketalization of o-Carbonyl Allylbenzenes: Synthesis of Benzobicyclo[3.2.1]octane Core

Abstract

CuI/DMSO-mediated intramolecular cycloacetalization/ketalization of o-carbonyl allylbenzenes has been achieved for constructing [6,6,5]-tricycles having a ketal motif in good yields. The expeditious one-step route provides a three C-O bond formation. The key products with the structural framework of a benzofused dioxabicyclo[3.2.1]octane core have been confirmed by X-ray crystallographic analysis. Synthesis of dihydroisocoumarin has been studied.

Diethylaminosulfur Trifluoride (DAST)-Mediated Intramolecular Benzannulation of o-Allylchalcones: Synthesis of 3-Fluorotetralins

“…Oxygenated 2-allylbenzaldehydes 3 were synthesized easily from commercially available isovanillin and 3-hydroxybenzaldehyde via a three-step synthetic route (O-allylation, Claisen rearrangement, O-alkylation) according to our previous reports. [23][24][25][26][27][28][29][30][31] Scheme 2 Synthetic route to the starting materials 1…”

Weakly Coordinating, Ketone-Directed Cp*Co(III)-Catalyzed C–H Allylation on Arenes and Indoles

“…ortho -Allyl aromatic ketones are very useful synthons for many biologically active natural products, and they are also used as important intermediates for different structural conversions . They can also serve as key building blocks to access several π-extensions directly .…”

Direct Synthesis of a Dioxabenzobicyclo[3.2.1]octane Core from Salicylaldehydes

“…9, 128.5, 127.0, 126.3, 125.5, 122.5, 120.3, 116.2, 86.6, 80.4, 77.4, 77.0, 76.6, 76.2, 38.1, 21.6;IR (neat) 3044, 2950IR (neat) 3044, , 2877IR (neat) 3044, , 1735IR (neat) 3044, , 1611IR (neat) 3044, , 1586IR (neat) 3044, , 1481IR (neat) 3044, , 1010 [1,4]dioxepine (3d): 3d was obtained as a colorless oil; 25.2 mg, 94% yield; 1 H NMR (300 MHz, CDCl 3 ) δ 7.34 (t, J = 7.9 Hz, 1H), 7.27−7.09 (m, 5H), 7.02−6.76 (m, 4H), 5.07 (d, J = 5.1 Hz, 1H), 4.48 (d, J = 10.2 Hz, 1H), 4.15 (d, J = 10.2 Hz, 1H), 3.84 (s, 3H), 2.65 (dd, J = 11.9, 5.1 Hz, 1H), 2.48 (d, J = 11.9 Hz, 1H); 13 C NMR (75 MHz, CDCl 3 ) δ 159. 7, 153.5, 140.1, 130.0, 129.6, 127.1, 125.4, 120.3, 117.6, 116.2, 113.1, 111.8, 86.4, 80.4, 77.4, 77.0, 76.6, 76.2, 55.2, 38.2;IR (neat) 2956IR (neat) , 2878IR (neat) , 2835IR (neat) , 1734IR (neat) , 1622IR (neat) , 1585IR (neat) , 1483IR (neat) , 1463 160.7, 153.4, 134.3, 134.3, 130.0, 127.4, 127.3, 127.1, 125.3, 120.4, 116.1, 115.5, 115.2, 86.1, 80.2, 77.4, 77.0, 76.6, 76.2, 38.1;IR (neat) 3047, 2951IR (neat) 3047, , 2878IR (neat) 3047, , 1897IR (neat) 3047, , 1737IR (neat) 3047, , 1610IR (neat) 3047, , 1513IR (neat) 3047, , 1231 7.12 (dd, J = 7.4, 1.5 Hz, 1H), 6.95−6.80 (m, 2H), 5.07 (d, J = 5.1 Hz, 1H), 4.49 (d, J = 10.2 Hz, 1H), 4.15 (d, J = 10.2 Hz, 1H), 2.65 (dd, J = 11.9, 5.1 Hz, 1H), 2.48 (d, J = 11.9 Hz, 1H); 13 C NMR (75 MHz, CDCl 3 ) δ 153. 7, 138.6, 130.1, 128.6, 128.2, 127.2, 125.6, 125.6, 120.4, 116.3, 86.6, 80.5, 77.6, 77.1, 76.7, 76.4, 38.3;IR (neat) 3066, 2922IR (neat) 3066, , 2821IR (neat) 3066, ,1735IR (neat) 3066, , 1626IR (neat) 3066, , 1517IR (neat) 3066, , 1235IR (neat) 3066, , 1150 2-(p-Tolyl)-2,3-dihydro-5H-2,5-methanobenzo[e][1,4]dioxepine (3g): 3g was obtained as a white solid, mp 70−72 °C; 13.9 mg, 55% yield; 1 H NMR (300 MHz, CDCl 3 ) δ 7.5...…”

“…Bochet et al successfully built the benzobicyclo skeleton by photochemistry of allenyl salicylaldehydes in 2008 . Very recently, Chang and co-workers reported a Cu/DMSO-mediated intramolecular cycloacetalization/ketalization of o -carbonyl allylbenzenes for successfully constructing dioxabenzobicyclo[3.2.1]­octane structures in good chemical yields (Scheme a) . Inspired by the rapid development of Prins-type reactions under Lewis acid or Brϕnsted acid conditions, , we describe a Cu­(II)-catalyzed Prins reaction to build a different dioxabenzobicyclo[3.2.1]­octane skeleton from salicylaldehydes and allyl alcohols under mild conditions (Scheme b).…”

“…6 Very recently, Chang and co-workers reported a Cu/ DMSO-mediated intramolecular cycloacetalization/ketalization of o-carbonyl allylbenzenes for successfully constructing dioxabenzobicyclo [3.2.1]octane structures in good chemical yields (Scheme 1a). 7 Inspired by the rapid development of Prins-type reactions under Lewis acid or Brϕnsted acid conditions, 8,9 we describe a Cu(II)-catalyzed Prins reaction to build a different dioxabenzobicyclo [3.2.1]octane skeleton from salicylaldehydes and allyl alcohols under mild conditions (Scheme 1b). Although there are many documented methods on the development of Prins reactions, the application of salicylaldehydes in Prins reactions is still very limited.…”