The first highly enantioselective Baeyer-Villiger oxidation of quaternary carbon-containing cyclobutane-1,3-diones using chiral phosphoric acid catalysis and commercially available oxidants was reported. According to the structure of the substrates, two optimized reaction conditions were developed to afford the corresponding chiral tetronic acid products in ≤93% and ≤95% ee values. This reaction offers the first catalytic asymmetric approach to chiral 5,5-disubstituted tetronic acid derivatives.
View Article and Find Full Text PDFA chiral phosphoric acid-catalyzed enantioselective condensation of 2,2-disubstituted cyclobutane-1,3-diones with a primary amine is described. This reaction offered a mild and efficient protocol for constructing quaternary carbon-containing cyclobutanes in good to high yields and enantioselectivities. This reaction is the first catalytic desymmetrizing carbonyl-amine condensation reaction and also represents the first catalytic desymmetrizing reaction of prochiral cyclobutane-1,3-dione.
View Article and Find Full Text PDFBackground: We investigated the reliability of core needle biopsy (CNB) in evaluating the status of hormone receptor (HR), human epidermal growth factor receptor (HER)-2, and Ki-67 status, and the effect of neoadjuvant chemotherapy (NAC) on the expression of these immunohistochemical markers.
Methods: Among 177 patients with breast adenocarcinoma, 95 patients underwent NAC and the remaining 82 patients made up the control group. Immunohistochemistry (IHC) was used to evaluate the expression status of estrogen receptor (ER), progesterone receptor (PR), HER-2, and Ki-67 in the specimens obtained by surgical excision or CNB.
Background: The aim of this study was to investigate the feasibility of sentinel lymph node biopsy (SLNB) after neoadjuant chemotherapy (NAC) in breast cancer patients with confirmed axillary nodal metastases.
Methods: We enrolled 51 patients with breast cancer who received NAC. All patients were proven to have axillary nodal metastases by histopathology biopsy prior to NAC.
Objective: To explore the value of sentinel lymph nodes (SLN) metastasis status in predicting the presence of residual disease in non-sentinel lymph nodes (nSLN) and the feasibility of avoiding or reducing the scope of axillary lymph node dissection (ALND) for patients with single positive SLN.
Methods: A retrospective study was conducted for 2265 patients with invasive breast carcinomas undergoing sentinel lymph nodes biopsy (SLNB) at Shandong Cancer Hospital between November 1999 and December 2011. And 1228 patients with axillary dissection were screened and divided into 5 groups of (-), (1/n), (1/1), (n/N), (n/n) (n ≥ 2, N ≥ 3, N > n) according to the status of SLN metastasis.
Background: The purpose of this study was to investigate the feasibility of avoiding axillary lymph node dissection (ALND) for patients with only one sentinel lymph node (SLN) metastasis. The characteristics and predictive factors for non-sentinel lymph node (NSLN) metastasis of patients with single positive SLN were also analyzed.
Methods: Patients with no and only one SLN metastasis (0/n and 1/n group, n ≥ 2) were selected from 1228 cases of invasive breast carcinoma, who underwent axillary dissection in Shandong Cancer Hospital between November 1999 and December 2011, to compare the characteristics of NSLN metastasis between them.