X‐ray investigations of bicyclic α‐methyl­ene‐δ‐valerolactones. III. trans‐(4aR,8aR)‐4a‐Methoxy‐3‐methyleneperhydro­chromen‐2‐one

The title compound, C₁₁H₁₆O₃, adopts a conformation in which the δ‐valerolactone and cyclo­hexane rings are almost coplanar with one another. The β‐methoxy substituent occupies an axial position with respect to the cyclo­hexane ring. The δ‐valerolactone moiety adopts a half‐chair arrangement, while the cyclo­hexane ring exists in a chair conformation.     

X‐ray investigations of bicyclic α‐methyl­ene‐δ‐valerolactones. II. (4aS,8aS)‐4a‐Methyl‐3‐methyl­eneper­hydro­chromen‐2‐one

The title compound, C₁₁H₁₆O₂, adopts a semifolded conformation with the δ‐lactone and cyclo­hexane rings almost perpendicular to one another. The β‐methyl substituent occupies an axial position with respect to the cyclo­hexane ring. The δ‐lactone moiety adopts a slightly distorted half‐chair arrangement, while the cyclo­hexane ring exists in an almost ideal chair conformation.     

(–)‐(1′S,4aS,7R,8aR)‐4a‐Ethyl‐7‐hydroxy‐1‐(1′‐phenylethyl)perhydroquinolinium bromide

In the structure of the title compound, C₁₉H₃₀NO⁺·Br^?, the rings of the perhydro­quinolinium moiety are cis fused. The successful reduction of the ketone functionality of the quinolinone used as starting material is confirmed by the hydroxy C—O bond length of 1.428 (3) Å.     

(4aR,8aS,9aR,10aS)‐8a,9a‐Difluoro‐1,4,4a,5,8,8a,9,9a,10,10a‐decahydroanthracene‐4a,10a‐diol hemihydrate

The title compound, C₁₄H₁₈F₂O₂·0.5H₂O, a hemihydrate of a C_s‐symmetric unsaturated difluorodiol, crystallizes in the centrosymmetric space group P2/m (Z = 4). The asymmetric unit contains two crystallographically independent difluorodiol half‐molecules, occupying the mirror planes at (x, 0, z) and (x, , z), and half a molecule of water, lying on the twofold axis at (0, y, 0). Four difluorodiol molecules self‐assemble around each solvent water molecule via O—H...O hydrogen bonds in a near tetrahedral symmetry to generate a cylindrical column‐like architecture.     

Radical‐initiated polymerization of β‐methyl‐α‐methylene‐γ‐butyrolactone

β‐Methyl‐α‐methylene‐γ‐butyrolactone (MMBL) was synthesized and then was polymerized in an N,N‐dimethylformamide (DMF) solution with 2,2‐azobisisobutyronitrile (AIBN) initiation. The homopolymer of MMBL was soluble in DMF and acetonitrile. MMBL was homopolymerized without competing depolymerization from 50 to 70 °C. The rate of polymerization (R_p) for MMBL followed the kinetic expression R_p = [AIBN]^0.54[MMBL]^1.04. The overall activation energy was calculated to be 86.9 kJ/mol, k_p/k_t^1/2 was equal to 0.050 (where k_p is the rate constant for propagation and k_t is the rate constant for termination), and the rate of initiation was 2.17 × 10^?8 mol L^?1 s^?1. The free energy of activation, the activation enthalpy, and the activation entropy were 106.0, 84.1, and 0.0658 kJ mol^?1, respectively, for homopolymerization. The initiation efficiency was approximately 1. Styrene and MMBL were copolymerized in DMF solutions at 60 °C with AIBN as the initiator. The reactivity ratios (r₁ = 0.22 and r₂ = 0.73) for this copolymerization were calculated with the Kelen–Tudos method. The general reactivity parameter Q and the polarity parameter e for MMBL were calculated to be 1.54 and 0.55, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1759–1777, 2003     

(1R,4bS,8aR)‐(1,2,3,4b,5,6,7,8,8a,9a‐Deca­hydro‐4,9a‐di­aza­fluoren‐1‐yl)­methanol

The crystal structure of the title compound, C₁₂H₂₀N₂O, was determined in order to establish the configuration of C4b (S) and C8a (R) with respect to the known configuration of C1 (R). The compound forms infinite chains of hydrogen‐bonded mol­ecules parallel to the c axis.     

[1a(1aα,5β,9aα)]‐1,1a,4,5,7,8,9,9a‐Octahydro‐3‐hydroxy‐1,1,2,5‐tetramethyl‐7‐methylene‐6H‐cyclopropa[3,4]cyclo­hept[1,2‐e]inden‐6‐one

Interest in the title structure, C₂₀H₂₄O₂, lies in the novel cis ring junction between the three‐ and seven‐membered rings. This stereochemical arrangement causes the methylene moiety and the cycloheptane ring to be twisted out of the plane of the aromatic ring. The cyclopropane ring is also twisted out of the plane of the aromatic system. The molecules are linked by an O—H?O hydrogen bond [O?O 2.741 (3) Å].     

Emulsion and controlled miniemulsion polymerization of the renewable monomer γ‐methyl‐α‐methylene‐γ‐butyrolactone

The kinetics of free‐radical emulsion polymerization of γ‐methyl‐α‐methylene‐γ‐butyrolactone (MeMBL), a renewable monomer related to methyl methacrylate, are presented in detail for the first time, and stable polymer latices are prepared. The effects of different reaction parameters on free‐radical emulsion polymerization of MeMBL are presented. Homogeneous nucleation is asserted to be the dominant path for particle formation. Miniemulsion copolymerization of MeMBL and styrene is also reported. In this case, the homogeneous nucleation process appears limited when using an oil soluble initiator. Both the RAFT miniemulsion polymerizations and RAFT bulk polymerizations are well controlled and narrow polydispersity copolymers are produced. Rate retardation is observed in the RAFT miniemulsion polymerizations compared with the free‐radical polymerization and RAFT bulk polymerizations and the possible causes of the retardation are discussed. The reactivity ratios of MeMBL and styrene in RAFT bulk copolymerization are also determined. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5929–5944, 2008     

(4R,4aR,6S,7S,7aS)‐6‐Hydro­xy‐7‐hy­droxy­methyl‐4‐methyl­per­hydro­cyclo­penta­[c]­pyran‐1‐one chloro­form solvate from Valeriana laxiflora

The structure of an iridolactone isolated from Valeriana laxiflora was established as (4R,4aR,6S,7S,7aS)‐6‐hydroxy‐7‐hydroxy­methyl‐4‐methyl­per­hydro­cyclo­penta­[c]­pyran‐1‐one chloro­form solvate, C₁₀H₁₆O₄·CHCl₃. The two rings are cis‐fused. The δ‐lactone ring adopts a slightly twisted half‐chair conformation with approximate planarity of the lactone group and the cyclo­pentane ring adopts an envelope conformation. The hydroxy group, the hydroxymethyl group and the methyl group all have β orientations. The absolute configuration was determined using anomalous dispersion data enhanced by the adventitious inclusion of a chloro­form solvent mol­ecule. Hydro­gen bonding, crystal packing and ring conformations are discussed in detail.     

N‐Benzyl‐4‐methyl‐N‐[(3aR*,4R*,7aR*)‐6,6,7a‐tri­methyl­per­hydro­inden‐4‐yl]­benzene­sulfon­amide

The synthesis, spectroscopic data and X‐ray structural analysis of the title compound, C₂₆H₃₅NO₂S, (I), are described. The crystal contains discrete mol­ecules separated by normal van der Waals distances. The benzene­sulfon­amide derivative of the corresponding amine allows the assigment of its relative configuration. The secondary amine has been synthesized via a sequential multi‐step hydro­formyl­ation procedure according to Eilbracht et al. [Chem. Rev. (1999), 99 , 3329–3365].).     

[(8a,9,9a‐η)‐9‐(η5‐Cyclopentadienyl)‐9‐nickelafluorenyl](η5‐pentamethylcyclopentadienyl)nickel(II)

The title compound, [Ni₂(C₅H₅)(C₁₀H₁₅)(C₁₂H₈)] or [Ni(C₁₀H₁₅){Ni(C₅H₅)(C₁₂H₈)}], is a rare example (and the first obtained from nickelafluorenyllithium) of an analogue of nickelocene in which the central Ni atom is coordinated to one pentamethylcyclopentadienyl ring and one nickelafluorenyl ring. Both rings lie almost parallel to one another: the dihedral angle between the planes which include these rings is 4.4 (1)°. Slip parameter analysis indicates that the bonding mode of the central Ni atom to the nickelacyclic ring is between η³ and η⁵. Two‐dimensional layers of molecules are formed by C—H...π interactions.     

(3R,4aS,5R)‐3‐Hydro­xy‐5‐isopropenyl‐3,8‐di­methyl‐4,4a,5,6‐tetra­hydro‐2(3H)‐naphthalenone

In the crystal structure of C₁₅H₂₀O₂, mol­ecules are associated by intermolecular hydrogen bonds between the hydroxy function and a keto group [O?O 2.770 (2) Å], forming chains along the [100] direction in the crystal. Both six‐membered rings in the decalin unit adopt envelope conformations; one section of the mol­ecule, encompassing the extended conjugation of a C=C double bond with an enone functionality [C=C—C=O = 175.6 (2)° and C=C—C=C = 176.6 (2)°], is flat, whilst the rest of the mol­ecule is folded relative to the constrained part. The stereochemistry was determined from the R‐(–)‐carvone starting material.