Extensions of a Basic Laboratory Experiment: [4+2] and [2+2] Cycloadditions

Abstract

Scheme II. The [2+4] thermal product from the reaction between trans-β-nitrostyrene and 2,3-dimethylbutadiene.

Insights into the Utilization and Quantification of Thermoplasmonic Properties in Gold Nanorod Arrays

“…The [4 + 2] cycloaddition between 2,3-dimethyl-1,3-butadiene (diene) and trans-β-nitrostyrene (dienophile) was chosen as a representative example (Figure 2a), as this reaction is solely heat driven. 41 Our intention was also to use the Diels−Alder cycloaddition as a model reaction to test the role of the morphology of AuNR arrays (straight vs bundled) on plasmonic heat generation. The photoirradiation of diene and dienophile, for ∼15 h, in the presence of bundled AuNR arrays (with NR length 1188 ± 162 nm) with a 1 W green laser, yielded ∼40% of the Diels−Alder adduct (1S,2R)-4,5-dimethyl-2-nitro-1,2,3,6-tetrahydro-1,1'-biphenyl (Figures 2b, S7−S9, and Table S1 in the Supporting Information).…”

“…Next, ∼880 mg (5.9 mmol) of trans-βnitrostyrene was mixed with 1 mL (8.8 mmol) of 2,3-dimethyl-1,3butadiene, and purged with nitrogen for ∼30 min. 41 Note, an excess of 2,3-dimethyl-1,3-butadiene was taken to compensate for evaporation losses during the course of the irradiation. The AuNR array was then irradiated with a 532 nm 1 W diode laser for ∼15 h. The reaction mixture after irradiation was dried using a rotary evaporator to remove the unreacted diene.…”

Web-Based 2D NMR Spectroscopy Practice Problems

“…At that time, it was clear that a vast majority of schools were teaching students to analyze IR spectroscopy and 1 H and 13 C NMR spectroscopy but only about 10–15% of schools were including 2D NMR spectral techniques. In the past 15 years, the number of laboratory experiments incorporating 2D NMR spectroscopy coupled with analysis has exploded in the chemical literature. − …”

Undergraduate Organic Experiment: Tetrazole Formation by Microwave Heated (3 + 2) Cycloaddition in Aqueous Solution

“…3−8 The most common among these is the Diels−Alder reaction. 3,4 Undergraduate students are typically exposed to (3 + 2) cycloaddition reactions during second-year undergraduate organic chemistry through reactions such as the oxidative cleavage of alkenes and alkynes by ozone, potassium permanganate, or osmium tetroxide. Most organic textbooks devote an entire chapter to pericyclic reactions, which includes a discussion about cycloadditions.…”

“…The use of microwave heating to accelerate reactions as part of undergraduate experiments has been described. − The authors in these previous reports have discussed the many advantages that microwave heating offers such as fast reaction times and high conversion rates. There are several reports that introduce pericyclic reactions into the organic teaching laboratory. − The most common among these is the Diels–Alder reaction. , Undergraduate students are typically exposed to (3 + 2) cycloaddition reactions during second-year undergraduate organic chemistry through reactions such as the oxidative cleavage of alkenes and alkynes by ozone, potassium permanganate, or osmium tetroxide. Most organic textbooks devote an entire chapter to pericyclic reactions, which includes a discussion about cycloadditions.…”