A practical and effective copper-catalyzed dehydrogenative Diels–Alderreaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.
Construction of Oxa-Bridged Tetracyclic Frameworks through a Prins Bicyclic Annulation
作者:Preethi N. Nair、Vangala Swathi、Ghaytadak Nishigandha、Balasubramanian Sridhar、Jithender G Reddy、Basi V. Subba Reddy
DOI:10.1002/ejoc.201801788
日期:2019.6.16
Aldehydes undergo smooth condensation with enediols in the presence of TMSOTf in dichloromethane to afford the corresponding hexahydro‐8a,4a‐(epoxyethano)pyrano[3,4‐f]isoindole‐1,3(2H,5H)‐dione derivatives in good yields.
在二氯甲烷中,在TMSOTf存在下,醛与烯二醇进行平滑缩合,得到相应的六氢-8a,4a-(环氧乙烷基)吡喃并[3,4- f ]异吲哚-1,3(2 H,5 H)-二酮衍生物良品率高。
Synthesis of constrained α-amino acid derivatives via Diels-Alder approach
Synthesis of new five and seven membered outer ring diene building blocks containing alpha-amino acid moiety and their usage in the preparation of the constrained amino acid derivatives is described. (C) 1998 Elsevier Science Ltd. All rights reserved.
Synthesis of benzocycloheptene-based amino acid derivatives via a [4+2] cycloaddition reaction as a key step
The seven-membered diene 5 is prepared from 2-butyne-1,4-diol using double orthoester Claisen rearrangement reaction as a key step. The Diels-Alder reaction of the diene 5 with various dienophiles followed by oxidation delivered the benzocycloheptene-based a-amino acid derivatives in very good yields. (C) 2001 Elsevier Science Ltd. All rights reserved.
Synthesis of 2,6-dioxabicyclo[3.3.0]octanes and 3,8-dioxabicyclo[4.4.0]dec-1(6)-enes by electrophilic cyclization of 3,4-dimethylene-1,6-hexanediols
作者:M. E. Gurskii、S. B. Golovin、M. O. Dekaprilevich、Yu. T. Struchkov、Yu. N. Bubnov
DOI:10.1007/bf00700900
日期:1995.7
3,4-Dimethylene-1,6-hexane diols 2 obtained by allylboration of ketones with 2,3-dimethylene-1,4-bis(dipropylboryl)butane 1 undergo cyclization on treatment with I-2/NaHCO3 to give 1,5-cis-di(iodomethyl)-2,6-dioxabicyclo[3.3.0]octanes (4) and/or 3,8-dioxabicyclo[4.4.0]dec-1(6)-enes (5). 4,4,9,9-Tetramethyl-3,8-dioxacyclodeca-1,6-dione (9) was synthesized by ozonolysis of bicyclic compound 5b. The structure of compound 5e was confirmed by X-ray diffraction analysis.