01935nas a2200241 4500008004100000022001400041245017900055210006900234260007500303300001600378490000700394520095700401653002401358653001401382653001401396653003001410653002601440100002301466700002701489700002401516700002701540856012601567 2015 eng d a0947-653900aIntramolecular cyclization of carbonate and thiocarbonate derivatives of myo-inositol in the solid state: implications for acyl group transfer reactions in molecular crystals0 aIntramolecular cyclization of carbonate and thiocarbonate deriva aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcSEP a13676-136820 v213 a

Racemic 4-O-phenoxycarbonyl and 4-O-phenoxythiocarbonyl derivatives of myo-inositol orthoformate undergo thermal intramolecular cyclization in the solid state to yield the corresponding 4,6-bridged carbonates and thiocarbonates, respectively. The thermal cyclization also occurs in the solution and molten states, but less efficiently, suggesting that these cyclization reactions are aided by molecular pre-organization, although not strictly topochemically controlled. Crystal structures of two carbonates and a thiocarbonate clearly revealed that the relative orientation of the electrophile and the nucleophile in the crystal lattice facilitates the intramolecular cyclization reaction and forbids the intermolecular reaction. The correlation observed between the chemical reactivity and the non-covalent interactions in the crystal of the reactants provides a way to estimate the chemical stability of analogous molecules in the solid state.

10acrystal engineering10acyclitols10ainositols10anucleophilic substitution10asolid-phase synthesis1 aTamboli, Majid, I.1 aShashidhar, Mysore, S.1 aGonnade, Rajesh, G.1 aKrishnaswamy, Shobhana uhttp://library.ncl.res.in/content/intramolecular-cyclization-carbonate-and-thiocarbonate-derivatives-myo-inositol-solid-001241nas a2200193 4500008004100000022001400041245014600055210006900201260000800270300001200278520049600290653002100786653002100807653002600828653003000854653002200884100001200906856012900918 2019 eng d a1434-193X00aUnusual route to synthesize indolizines through a domino SN2/michael addition reaction between 2‐mercaptopyridine and nitroallylic acetates0 aUnusual route to synthesize indolizines through a domino SN2mich cJAN a765-7693 a

A straightforward synthesis of indolizines has been demonstrated from the reaction of 2‐mercaptopyridine and nitroallylic acetates in the presence of a base. The products were obtained in good isolated yield under relatively mild reaction conditions. The mechanistic insight of the reaction has been revealed by performing some control experiments demonstrating that the reaction is initiated by a sequential SN2/Michael addition reaction followed by removal of the sulfur moiety.

10adomino reactions10aMichael addition10anitrogen heterocycles10anucleophilic substitution10asynthetic methods1 aRoy, S. uhttp://library.ncl.res.in/content/unusual-route-synthesize-indolizines-through-domino-sn2michael-addition-reaction-between-201779nas a2200205 4500008004100000245010700041210006900148260000800217300000700225490000700232520105500239653002001294653003001314653001801344653002701362100001701389700001901406700001901425856012901444 2022 eng d00aNucleophilic substitution at a coordinatively saturated five-membered NHC center dot haloborane centre0 aNucleophilic substitution at a coordinatively saturated fivememb cJUL a970 v103 a

In this paper, we have used a saturated five-membered N-Heterocyclic carbene (5SIDipp = 1,3-bis-(2,6-diisopropylphenyl)imidazolin-2-ylidine) for the synthesis of SNHC-haloboranes adducts and their further nucleophilic substitutions to put unusual functional groups at the central boron atom. The reaction of 5-SIDipp with RBCl2 yields Lewis-base adducts, 5-SIDipp center dot RBCl2 [R = H (1), Ph (2)]. The hydrolysis of 1 gives the NHC stabilized boric acid, 5-SIDipp center dot B(OH)(3) (3), selectively. Replacement of chlorine atoms from 1 and 2 with one equivalent of AgOTf led to the formation of 5-SIDipp center dot HBCl(OTf) (4) and 5-SIDipp center dot PhBCl(OTf) (5a), where all the substituents on the boron atoms are different. The addition of two equivalents of AgNO3 to 2 leads to the formation of rare di-nitro substituted 5-SIDipp center dot BPh(NO3)(2) (6). Further, the reaction of 5-SIDipp with B(C6F5)(3) in tetrahydrofuran and diethyl ether shows a frustrated Lewis pair type small molecule activated products, 7 and 8.

10aNHC-haloboranes10anucleophilic substitution10asaturated NHC10atetra-coordinate boron1 aKundu, Gargi1 aTothadi, Srinu1 aSen, Sakya, S. uhttp://library.ncl.res.in/content/nucleophilic-substitution-coordinatively-saturated-five-membered-nhc-center-dot-haloborane