One-Pot Synthesis of Nitrogen Heterocycles Initiated by Regio- and Diastereoselective Carbon−Carbon Bond Formation of Bifunctional Carbonyl Compounds

Abstract

We report a one-pot synthesis of nitrogen heterocyclic compounds initiated by the allylation of the formyl group of bifunctional carbonyl compounds accompanying chemo-, regio-, and diastereoselective carbon-carbon bond formation in side chain moieties.

Transition‐Metal‐Free Coupling Reaction of Vinylcyclopropanes with Aldehydes Catalyzed by Tin Hydride

“…In the next stage, we focused on the use of tin adduct 2 a as a coupling partner because allylic halogenotin reagents can promote the allylation of aldehydes without the use of Lewis acids 19. This is an advantage of using iodotin (Bu 2 SnI‐) species over conventional trialkyltin (Bu 3 Sn‐) species because allyltributyltin‐promoted allylation of carbonyl compounds generally requires acceleration by Lewis acids 12.…”

“…In the next stage, we focused on the use of tina dduct 2a as ac oupling partner because allylic halogenotin reagents can promote the allylation of aldehydes without the use of Lewis acids. [19] This is an advantage of using iodotin( Bu 2 SnI-) species over conventional trialkyltin (Bu 3 Sn-) species because allyltributyltin-promoted allylation of carbonyl compounds generally re-quires acceleration by Lewis acids. [12] Thus, after the hydrostannation of 1a at room temperature for 48 hi nt he presence of ar adical initiator V-70L, the addition of PhCHO to the reaction mixture gave homoallyl alcohol 3a (Scheme 3).…”

One‐Pot Synthesis of Heterocycles Initiated by Chemoselective Reduction of Bifunctional Carbonyl Compounds

“…While the reason why the ClBu 2 SnN-nucleophile did not work well here in comparison with the reaction involving allylation [9] is not yet clear, Bu 3 SnN moieties have fundamentally higher nucleophilicity than ClBu 2 SnN moieties because of the presence of the electron-withdrawing Cl sub- stituents in the latter case. Hence, Bu 3 SnN moieties worked effectively in the presented conjugate addition.…”

“…We have recently reported the synthesis of nitrogen heterocycles initiated by the allylation of 1, [9] by treatment with dibutylchlorotin nucleophiles (Bu 2 ClSn-allyl)/HMPA. The reason why dibutylchlorotin derivatives worked well is their high reactivity towards the formyl groups of 1 in the initial allylation, whilst allylic tributyltin compounds, (Bu 3 Sn-allyl)/HMPA, show no reactivity towards 1.…”

One-pot synthesis of heterocyclic compounds initiated by chemoselective addition to β-acyl substituted unsaturated aldehydes with nucleophilic tin complexes

“…Next, a one-pot synthesis of nitrogen heterocyclic compounds was carried out initiated by the allylation of the formyl group of bifunctional carbonyl compounds 1 [20]. The generated tin-oxygen bonds worked as key intermediates to prepare various heterocyclic compounds accompanying chemo-, regio-and diastereoselective carbon-carbon bond formation in the side chain moieties.…”