Electrophilic Cyclization and Intermolecular Acetalation of 2-(4-Hydroxybut-1-yn-1-yl)benzaldehydes: Synthesis of Diiodinated Diepoxydibenzo[c,k][1,9]dioxacyclohexadecines

Cascade Cyclization of o-(2-Acyl-1-ethynyl)benzaldehydes with Amino Acid Derivatives: Synthesis of Indeno[2,1-c]pyran-3-ones and 1-Oxazolonylisobenzofurans via the Erlenmeyer-Plöchl Azlactone Reaction

A highly regioselective divergent approach is reported for the synthesis of both indeno[2,1-c]pyran-3-one and 1-oxazolonylisobenzofuran derivatives using the Erlenmeyer-Plöchl azlactone (EPA) reaction. This approach involves the synthesis of o-(2-acyl-1-ethynyl)benzaldehydes, which reacted with various amino acids. Reaction with N-acylglycines resulted in the formation of indeno[2,1-c]pyran-3-ones, involving the sequential formation of two C-C bonds and two C-O bonds. Conversely, when the same conditions were applied to free amino acids, 1-oxazolonylisobenzofurans were obtained. This reaction involved the formation of a C-C bond between oxazolone and o-(2-acyl-1-ethynyl)benzaldehyde, followed by the formation of a C-O bond through a selective 5-exo-dig cyclization.

Iodine promoted cascade cycloisomerization of 1-en-6,11-diynes

An iodine promoted cascade cycloisomerization of 1-en-6,11-diynes is presented for the easy preparation of tetrahydrobenzo[f]isoquinolines. This developed reaction system is identified as having good functional-group applicability and can be scaled up to gram quantities. In this transformation, two new cyclic frameworks and one carbonyl group are formed with four new bonds constructed. Additionally, the resulting iodo-substituted compounds could be further derived through simple elimination reactions.

Synthesis of 3-phosphinoylbenzofurans via electrophilic phosphination cyclization

An expedient strategy for the synthesis of 3-phosphinoylbenzofurans through a cascade electrophilic phosphination cyclization has been presented.