New synthetic methods for the regioselective annelation of aromatic rings: 1-hydroxy-2,3-disubstituted naphthalenes and 1,4-dihydroxy-2,3-disubstituted naphthalenes

Tandem reversible addition–intramolecular lactonization for the synthesis of 3-functionalized phthalides

“…14 Although there are a variety of strategies for the synthesis of quinones, 15-17 phthalide annulation is an especially useful methodology resulting in a facile, one-pot process. This annulation reaction was originally developed in the late 1970s by Hauser and Kraus,18,19 where phthalides 3 (Hauser-Kraus donors) were reacted with Michael acceptors 4, under strongly basic conditions, generating substituted naphthalene products 5 (Scheme 2).A variety of substituted quinone skeletons for highly substituted natural product synthesis can be prepared using phthalide derivatives 3, and also those having different substitution patterns on the aromatic ring. The aromatic substituents on phthalide 3, however, affect the regioselectivity in annulated product formation.…”

“…14 Although there are a variety of strategies for the synthesis of quinones, [15][16][17] phthalide annulation is an especially useful methodology resulting in a facile, one-pot process. This annulation reaction was originally developed in the late 1970s by Hauser and Kraus,18,19 where phthalides 3 (Hauser-Kraus donors) were reacted with Michael acceptors 4, under strongly basic conditions, generating substituted naphthalene products 5 (Scheme 2).…”

Regiospecific Synthesis of 7‐Hydroxyindoles from Pyrroles by Anionic Benzannulation

“…Keeping the regiochemical issues in mind, we chose to employ the van Leusen annulation [17] and Hauser annulation [18] to the pyrrole synthons. Although the principle of the annulations, i.e., the sequence of lateral deprotonation, Michael addition, Dieckmann condensation, and elimination, is well established, their success is unpredictable.…”

The design of 8-hydroxyquinoline tetracyclic lactams as HIV-1 integrase strand transfer inhibitors

“…Instead, we sought to fundamentally redesign the lactone coupling partner in order to decrease the pKa of the benzylic position. [36,37] Synthesis of such a substrate commenced with activation of benzylic alcohol 8 with methanesulfonyl chloride and subsequent displacement with sodium cyanide (Scheme 3). The 2-chloropyridine 17 was then carbonylated in the presence of methanol to afford methyl ester 18.…”

“…To an ice cold suspension of potassium carbonate (38.6 g, 0.28 mol) and diethyl 1-diazo- (37). 11-oxo-6,6a,7,8,9,11-hexahydroindolizino[7,6-g]quinoline-5-carbonitrile (42).…”