Intramolecular conjugate addition reactions of amines and carbamates to 2,5-cyclohexadien-1-ones: Stereoselective synthesis of perhydroindoles

2‐(Trimethylsilyl)ethanesulfonyl (or SES) Group in Amine Protection and Activation

“…The intramolecular reaction was used in the total synthesis of the pentacyclic structure of Manzamine A, 37,115,116 aziridines, 117 (Scheme 35) and analogues of biological molecules. 12 During the synthesis of the marine alkaloid Manzamine A, 45,115 a 15-membered macrocycle was formed in a good yield using the usual alkylation conditions (eq 18).…”

Stereoselective Synthesis Using Diastereotopic Groups

“…When the reaction was repeated at 25°C, the kinetically preferred 30 was the major product. 21 After modification of the side chains, i.e. going to 32, acid catalysed bicyclisation led to 33 as the major product in 88% yield.…”

“…going to 32, acid catalysed bicyclisation led to 33 as the major product in 88% yield. 21 Kinetic control was realised on cyclisation of 34 with NaHCO 3 in MeOH. This resulted in 35 as the exclusive product.…”

Synthesis of Indolines via a SmI2 Promoted Domino Nitro Reduction–Intramolecular aza‐Michael Reaction

“…It is known that in the presence of triphenylphosphine, that azide functional group bearing acyclic ‐α,β‐unsaturated carbonyl and cyano compounds spontaneously cyclize upon reduction to afford pyrrolidines or piperidines in good yields . Furthermore, carbamates and sulfonamides can undergo intermolecular cyclizations with α,β‐unsaturated carbonyl compounds in the presence of a simple base such as sodium tert ‐butoxide or sodium hydrogen carbonate (Scheme ). An article relevant to this work was published in the year 2000 in which Bunce and coworkers demonstrated that the exploitation of a nitro group in a tandem reduction–intramolecular Michael addition protocol could efficiently provide nitrogen heterocycles such as 2‐(tetrahydroquinolin‐2‐yl)‐, 2‐(3,4‐dihydro‐2 H ‐benzo[ b ][1,4]oxazin‐3‐yl)‐ and 2‐(tetrahydroquinoxalin‐2‐yl) acetates in good yield when simply employing iron powder in glacial acetic (Scheme ) .…”