Stereoselective free radical cycloaddition-macrocyclization in facile synthesis of trans-cyclohexano-fused 12-membered crown thioethers

Addition of Perfluoroalkylethane Thiols to Bis(Propargyl) Polyoxyethylene Ethers: Synthesis of Tetrakis-(F-Alkylethanethio) Polyoxyethylene Ethers

“…Whereas in the case of the ionic addition of thiol on thioenol ethers which gave the 1,1-disulfur product 15 , the proton linked to the disulfur carbon is more shifted to low fields (∼4.8 ppm). These reactions are in good agreement with those reported in the literature, 16 and show the formation of the most stable radical product that determines the orientation of these radical additions (Scheme 2).…”

Trans-2-aminocyclohexanols as pH-triggered molecular switches

“…Conformational control via introduction of various substituent(s) into a trans-fused six-membered cycle was proposed by us as a new principle for modification of the complexing ability of (cyclohexano)crown compounds and non-macrocyclic ionophores (podands). [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Similar ideas were suggested for cyclohexanebased podands by Raban et al [24][25][26][27] In these structures, a substituent plays a role of 'conformational lever', or 'counterbalance', and the cyclohexane moiety serves as a mechanical transmitter. The cyclohexane machinery can also mimic an allosteric effect by transmitting a conformational change (signal) from one complexing center (e.g.…”

Cyclohexane-Based Conformationally Controlled Crowns and Podands

“…This conformational shift was described as a 'contraction effect' of the macrocycle [4][5][6][7]9,11,[13][14][15][16][19][20][21]. Its magnitude was measured as a deviation of the free energy difference for the A B equilibrium (∆G B-A ; see Table 1 ) from the analogous parameter for t r a n s -1 , 2dimethoxycyclohexane, and was estimated as 2.7 kJ/mol for 3 [9] and 3.7 kJ/mol for 4 [4].…”

“…Conformational control via introduction of various substituent(s) into a trans-fused six-membered cycle was proposed by us as a new principle for modification of the complexing ability of (cyclohexano)crown compounds and non-macrocyclic ionophores (podands) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Similar idea was suggested for cyclohexane-based podands by Raban et al [22][23][24][25].…”